Shows
The APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Episode 62: Molecular Structure and Acid StrengthAll hydrohalic acids, but hydrofluoric acid, are strong acids. Why is that (0:31)? Strong acids fully dissociate and have a large Ka, weak acids only dissociate to a small percentage (1:20). When looking at strength, we are comparing the stability of the conjugate acid/base pair partners (2:00). For binary acids across a period (2:37) as well as down a group (3:09) electronegativity determines acid strength. For oxyacids, we can compare acids with different numbers of oxygen atoms, which affects the inductive effect, as well as resonance structures (4:58). We can also discuss acid strength across a period (6:44) and down a group (7:34). Bases are proton...2022-01-3110 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Episode 61: Unit 7 Selected FRQsThe FRQ questions on the AP exam often combine content from two or three different units. In today’s episode, we are emphasizing questions that require knowledge and skills from Unit 7: Equilibrium. You will rarely find an FRQ that solely focuses on Unit 7, since it lays the foundation for Unit 8, acids and bases as well as parts of Unit 9, Application of Thermodynamics. It also links back to concepts from earlier units, like gas laws. The questions we are using today are online accessible. Our suggestion: Answer the questions yourself and then listen to this episode to hear the explanations, as...2022-01-2412 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Episode 60: Factors Affecting the Dissolution of a SaltThis episode is an application of earlier discussed concepts. In episode 33 we talked about disruptions affecting equilibrium: concentration, temperature and pressure. In episode 34, solubility equilibria, we talked about the dissolution of a salt. In this episode we set our focus a bit differently: We look at environmental factors, like pH or other dissolved ions and how they affect the dissolution of a salt. pH was a concept introduced in Unit 4 with more in depth coverage in unit 8 It's all connected. So, let’s recap the recaps that lay the foundation for this episode, then introduce the new concepts and di...2022-01-1809 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Episode 59: Unit 6 selected FRQsUnit 6 is all about the big idea Energy (0:46). Episode 59 discusses the questions 2021 - Question 4, 2017 - Question 5 and 2013 - Question 3. These are released FRQs from previous exams and copyright of the College Board.Question 4 of the 2021 exam starts with our favorite equation: mcAT (1:34). In part b) you calculate the mass of iron and in part (c) discuss the effect of doubling the mass of iron on the maximum temperature. Question 5 of the 2017 looks at similar concepts, but it is a combustion reaction (3:40). It starts again with calculating the magnitude of heat energy and using mcAT. In part (b...2021-12-2013 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Episode 58: Energy of Phase ChangesWe are taking a closer look at what happens when hot water is cooled down or ice is heating up (0:30).After a brief review of the terminology of phase changes (1:11) we are taking a closer look at the particles in solid, liquids and gases (1:29). Focusing on the energy component of phase changes, we are describing the five segments of a heating curve (2:22). In segments where the temperature increases with increasing heat added, we are increasing the particle motion and can calculate the heat added using mCΔT (3:26). In segments where the temperature is not increased, the energy a...2021-12-0610 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Episode 57: Unit 5 selected FRQsUnit 5 is often a stand alone unit and offers a unique perspective on reactions. Episode 57 discusses the questions 2010B - Question 6 and 2019 - Question 6. These are released FRQs from previous exams and copyright of the College Board (0:44).Question 6 of the 2010B exam focuses on the synthesis of hydrogen chloride from its elements (1:33). We are asked to determine the order of reaction for both reactants and justify the answer.Question 6 of the 2019 exam looks at a decomposition reaction and the data collected is graphed in three graphs. We can use the graphs to identify the reaction...2021-11-2912 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Episode 56: Concentration Changes Over TimeAn AP Chemistry classic experiment for concentration changes over time is determining the rate law of fading Crystal Violet. (1:07) If the reaction is zero order, the plot of our concentration of our reactant vs time is linear. (2:51) If the reaction is first order with respect to our crystal violet, a plot of the natural log of the concentration of the reactant vs time will be linear. (3:17) If the reaction is second order with respect to crystal violet, a plot of 1 over concentration vs time will be linear. (3:45) We can use the graph and determine k as follows: for zeroth...2021-11-2209 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Episode 55: Unit 4 Selected FRQsUnit for is a mix of foundational skills, like stoichiometry, and an introduction to later topics (0:32). The questions in this episode are: 2018 - Question 3 d) through i) and 2014 - Question 1 a) - f).These are released FRQs from previous exams and copyright of the College Board (1:32). 2018 starts with three questions from a different unit. Part d) asks for a redox reaction (2:05). In part e) you are asked to calculate the concentration of iron(ii)plus in the solution (2:36) and in f) to discuss lab equipment (3:58). G) and i) refer to a second experiment involving iron impurities (4:39) and...2021-11-1511 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Episode 54: Unit 3 Selected FRQsThe FRQs discussed in this episode are the question 4s from the 2019, 2018 and 2017 AP Exam. These are released FRQs from previous exams and copyright of the College Board (0:23).Question 4 of the 2018 exam focuses on comparing the IMFs of CS2 and COS, asking you to explain why CS2 has a higher boiling point (1:48). The second part has you calculate the pressure of CS2 using the ideal gas law (3:11). In question 4 of the 2019 exam you describe the effect of raising the temperature on the motion of the CO2 particles connecting temperature and particle speed (4:09). In part b you calculate...2021-11-0812 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Episode 53: Beer-Lambert LawCoffee needs to be “just right” and we can tell how strong it is by the color (0:30). We can use the color to determine concentration also in Chemistry (1:09). The color we see is determined by the wavelength an object reflects, while absorbing all other colors (1:23).The Beer-Lambert Law absorbance to molar absorptivity, path length and concentration (2:08). In AP Chemistry, the molar absorptivity and path length are held constant, therefore absorbance is directly proportional to concentration (2:28).Experimentally, we measure absorbance using spectrophotometers (4:41). To determine the concentration of, for example, blue dye in a sports drink, we have...2021-11-0108 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Episode 52: Deviation From Ideal Gas LawTeachers wish students would always behave ideal, but in reality life happens and it gets messy (0:32). The same is true for gases: There is a difference between real and ideal gases (1:12). The Ideal Gas Law assumes that particles don’t experience intermolecular forces nor that they take up volume (1:34). But real gases do and this leads to deviations from the Ideal Gas Law, especially under high pressure and close to condensing (2:00). Under low temperatures, intermolecular forces become more and more significant (2:41), leading to a lower pressure of a real gas compared to an ideal gas (3:30). This is enhanced by th...2021-10-1807 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Episode 51: Types of Solids and Their PropertiesSitting in your room, you might have salted peanuts as a snack, a pencil, tea with sugar and you listen to this episode with earphones in (0:31). Sodium chloride, sugar, graphite and copper represent four types of solids. Sodium chloride is an ionic solid with low vapor pressure, high melting points and high boiling points, because of the strong attractive forces. Sugar is a molecular compound with low melting points due to weak IMFs (1:22). Graphite is an example of a network covalent solid (5:29), which generally have high melting points. Copper is representative of a metallic solid, which are good conductors...2021-10-0410 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Selected Unit 1 and 2 Free-Response QuestionsThe FRQs discussed in this episode are 2008 - Question 2 and 5 as well as 2019 question 5. These are released FRQs from previous exams and copyright of the College Board (0:22).Question 2 of the 2008 focuses on the experimental approaches, first the determination of the formula of a hydrate (2:06) and then gravimetric analysis (3:33). Question 5 of the 2008 exam starts with questions about ionization energies for fluorine in comparison with oxygen and xenon. The second part of the question asks for Lewis Diagrams of xenon compounds (7:59), the geometric shape (8:25) as well as hybridization (8:35) and polarity (8:55).Question 5 of the 2019 exam provides a PES...2021-09-2712 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Lewis Diagrams and Formal ChargesLewis Diagrams give us information about the arrangement and bond order of compounds (0:23). There are four steps to write Lewis Structure: 1) Sum up available valence electrons (1:16), 2) write symbols and connect them with a single bond (1:57), 3) complete the octet for surrounding atoms (2:27), and 4) add remaining electrons as lone pairs on central atom (2:48).Some elements, like hydrogen, boron and beryllium as well as elements in Period 3 and beyond are exceptions to the octet rule (3:24). Formal charges can be used to determine the best Lewis Structure (5:15). In our episode we discuss calculating the formal charge for two possible structures of...2021-09-2009 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Gravimetric AnalysisDo you have your own bathroom? Then you might be familiar with soap scum, which is the result of a combination of having hard water and soap (0:44). To determine how hard water is, we can use gravimetric analysis, which is an experimental procedure used to determine the amount of a substance, for example an ion, by precipitating it from an aqueous solution (1:25). Basing off of the solubility rules (1:45), the episode describes the steps to precipitate the calcium carbonate with sodium carbonate (3:05) and briefly discusses how to calculate the water hardness (5:08) and calcium ion concentration (5:38). Experimental errors described in the...2021-09-1308 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Empirical and Molecular FormulasSwitching glucose and formaldehyde would be really bad (0:42)! So let’s make sure we know the difference between empirical and molecular formulas! Our episode starts with a definition of empirical formulas (1:20) and the comparison of ionic and molecular compounds (1:49). It briefly recaps the significance of a chemical formula (2:16) and then recaps the steps to calculate an empirical formula using glucose as an example (2:50). But what if you do not have a whole-number ratio right away (5:30) and how do you go from Empirical to Molecular Formula (6:14)? One specific type of calculation is the combustion analysis (7:11).Question: What is th...2021-09-0609 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Test Taking Tips 2021The episode discusses and compares the structure of the two exam formats: the paper exams in May and the digital exam in June (0:50). Differences between the administration of the digital exam and paper exam are described (1:11), especially the calculator policies (2:16). We are taking a quick look at timing, which is the same for the paper exam and the digital exam (4:26). Your last episode of the season ends with a quick recap of test taking tips for multiple-choice questions (4:57) as well as free-response questions (5:33). Good luck everyone!Thank you for listening to The APsolute RecAP: Chemistry Edition!2021-05-0308 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - FRQ AnnotationsThe FRQ section has 3 long and 4 short question sets which you will have 105 minutes to complete (0:52). Past free response questions are available on the College Board website. (1:32) Make sure you carefully read the question and answer directly with precise language. (2:59) For calculations, make sure you show all your work, use units throughout and report your answer with the correct number of significant figures. (6:16)True or False: You are not allowed to bring a highlighter to mark information in the exam booklet.Thank you for listening to The APsolute RecAP: Chemistry Edition!(AP is...2021-04-2609 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Multiple Choice StrategiesYou’ve made it through the year! Let’s hone our Multiple Choice skills to make sure we can show off our knowledge and skills! Our episode starts by discussing pacing: The multiple choice section consists of 60 questions within 90 minutes (0:54). Then we are taking a closer look at strategies: using the process of elimination (2:09), carefully reading and circling key information (2:47), mental math and estimations (4:20), and most importantly: practice, practice, practice (5:04).How many Multiple-Choice questions will be on the 2021 digital exam?Thank you for listening to The APsolute RecAP: Chemistry Edition!(AP is a regi...2021-04-1907 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Listener’s Choice IIIOur listener’s choice recaps three topics: (R)ICE tables, titrations and buffers. We start with the RICE table - what does it actually stand for? (0:49). RICE tables are best explained with an example. In our case: The reaction of gaseous hydrogen with gaseous chlorine to form gaseous hydrogen chloride - a reaction that has a K = 49. And we are calculating the concentrations at equilibrium (1:44)! Two important tips for RICE tables: (1) practice, practice, practice; (2) make assumptions (4:09).Our next two topics are connected: titrations and buffers. We start with the titration of a strong acid/strong base and di...2021-04-1213 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - ElectrolysisElectroplating is an important industrial process to prevent corrosion and upvalue jewelry and cutlery (0:30). Electroplating takes place in electrolytic cells, which need an external power source (1:25). Our episode qualitatively describes electroplating using the example of a zinc spoon and silver (1:52). Quantitatively, we discuss Faraday’s law and the relationship between electric charge, current, time and Faraday’s constant first theoretically (3:41) and then with an example problem asking how much silver is being produced when applying 5.0A for 31 minutes (5:07).Question: Electrolysis can also be used to produce or refine metals in electrometallurgy. What is the name of the elec...2021-04-0508 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Galvanic and Electrolytic CellsHave you ever built a lemon battery? How do they work? (0:32). We are distinguishing between two types of electrochemical cells: galvanic, also called voltaic cells, and electrolytic cells (1:05). Both cells have an anode, where the oxidation takes place, and a cathode, where the reduction occurs. (2:01). But where are the differences? Our episode describes the set-up of a galvanic cell (4:25) as well as electrolytic cell (5:09) and the function of all components.Question: What metal (oxide) is used in common household batteries?Thank you for listening to The APsolute RecAP: Chemistry Edition!(AP is a...2021-03-2907 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Gibbs Free EnergyOur episode starts with a clarification of using the terms thermodynamically favored vs spontaneous (1:19). To determine if a reaction is thermodynamically favored, we calculate Gibbs Free Energy using the Gibbs Free Energy of formation (2:45). Taking a closer look at Gibbs Free Energy we relate it to enthalpy and entropy and look at four different situations: exothermic and increase in entropy as well as endothermic and decrease in entropy don’t require calculations (3:37). But what if I have a reaction that is endothermic but increases entropy (5:46) or a reaction that is exothermic and decreases entropy (6:36)? We have to take the te...2021-03-2209 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - EntropyClick, click, click - you picture has been taken! Our episode starts with describing entropy with respect to the dispersal of matter and compares it to the snapshots or microstates (0:30). The phase changes are examples of increases of dispersal of matter (1:06). Entropy can also be defined as an increase of the dispersal of energy and therefore we tie it to KMT (3:50). The change in entropy can be calculated by subtracting the sum of the entropy of the reactants from the sum of the entropy of products (4:53).Question: What is the sign of ΔSo for the formation of N...2021-03-1507 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - BuffersBuffers are a common term in the english language, but what do they mean in Chemistry (0:39)? Episode 38 describes the chemical set up of buffers (1:31) and takes a closer look at how the buffer works on a particle level (2:03). To calculate the pH of a buffer the episode describes the Henderson-Hasselbalch equation (3:04). Using the theme of equal concentration of conjugate acid/base pair, two approaches to prepare a buffer solution are described (5:39) and the concept of buffer capacity is being discussed (6:36).Question: How does a smaller concentration of conjugate base than weak acid affect the pH of a...2021-03-0809 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Acid-Base TitrationsAcid-base titrations are an experimental approach to determine the concentration of an unknown acid or base (0:56). Your episode starts by introducing the terms analyte and titrant (1:49) and looks at two examples: In the first example, we are titrating a strong acid with a strong base (2:03). We describe the shape of the titration curve (2:14) and define equivalence point (2:44), the point at which the number of moles of titrant and number of moles of analyte are the same. Using the equivalence point, we can calculate the molarity of the unknown analyte (3:03). The second example outlines the titration of a weak acid...2021-03-0108 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - pH and pOHWe are starting with a recap of episode 35 and are defining acids and bases and their connection to pH and pOH (1:02). Taking a closer look at the pH scale, our episode discusses the use of logarithm for pH and pOH (1:53). This lays the foundation for the calculation of pH and pOH for strong acids and bases. For weak acids and bases the episode draws the connection back to equilibrium and introduces the acid/base ionization constant (3:10), which is needed together with the initial concentrations to calculate the pH of a weak acid/base (6:08).Question: You have a 0.1...2021-02-2210 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Acids and Bases - The BasicsWe start our recap with a recap: What are acids and bases and acid-base reactions (1:03)? Diving a bit deeper, we take a closer look at the dissociation of acids (2:20), which releases H+ ions and therefore lowers the pH. Vice-versa we look at the dissociation of bases in water (3:34 ) and it’s connection to pOH and pH (3:34). Taking a closer look at water, which is an amphoteric substance (4:16), the episode introduces the autoionization of water (5:56) and the equilibrium constant: KW (6:35) and ties it to pH and pOH (7:29).Question: At a higher temperature, will the pH of a neutral so...2021-02-1510 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Solubility EquilibriaOur episode starts with addressing the question: What IS solubility? (1:19). The episode introduces solubility equilibria with respect to the Solubility-Product Constant, K, expression (1:57) and discussion how its magnitude relates to solubility (3:05). If you have the Ksp you can calculate the molar solubility - in mol/L - as well as the mass solubility in g/L (4:35). Comparing K to Q let’s you determine if a precipitate forms (5:58).Question: How does a common ion affect the solubility of a salt?Thank you for listening to The APsolute RecAP: Chemistry Edition!(AP is a re...2021-02-0808 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Le Chatelier’s PrincipleLet’s be disruptive: What happens when you disturb the equilibrium of a chemical reaction? Our episode talks you through several different scenarios and their effect on the reaction as well as K and Q: We can add reactant and product (2:01) or remove reactant and products (2:58). We can also change the temperature of our reaction and either add heat (4:29) or lower the temperature (5:35). If we have gaseous, we can also change the pressure by changing the volume of the container (5:59).Question (7:48): Which reaction is favored if you decrease the volume and have the same number of gaseous pa...2021-02-0108 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Equilibrium ConstantTry to keep your balance! The episode starts with an analogy of villagers commuting from Moleville to Chemtown (0:59). Tying it to a chemical reaction, we define equilibrium as the point where the rate of the forward and the rate of the reverse reaction are the same (1:43). To determine if, at equilibrium, a reaction has more reactants or products, we can calculate the equilibrium constant, capital K (3:59) and write the equilibrium expression (4:34). The magnitude of K tells us if a reaction favors the products or the reactants (5:35). To determine if a reaction is at equilibrium, we can calculate Q (6:12).2021-01-2509 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - EnthalpyHeat, Energy and now Enthalpy? What is going on? Our episode starts by defining and distinguishing between these concepts (0:54) before taking a closer look at enthalpy itself. The episode connects the mathematical sign of enthalpy to the heat being absorbed / released (1:39) and discusses the extensive character of enthalpy (2:06) as well the value of reversed reactions (2:23) and its dependency on the state (2:47). We also recap two approaches to calculate the enthalpy of a reaction: taking into account the bonds broken and bonds formed (3:06) as well as the standard enthalpies of formation (5:25). To clarify the calculations using the standard enthalpies of...2021-01-1810 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Heat Capacity and CalorimetryHeat transfer is all around! The episode starts by describing the heat transfer on a particle level (0:58). Heat transferred can be quantified using the heat transfer equation (1:42). The heat transfer equation takes into account the mass of the substance (2:32), the specific heat capacity (4:12) as well as the change in temperature (6:05). It can be measured in an experimental set up by using calorimetry (6:18).Question (8:01): What is the molar heat capacity of water in J/mol K?Thank you for listening to The APsolute RecAP: Chemistry Edition!(AP is a registered trademark of the College...2021-01-1108 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Energy of Chemical ReactionsWe are surrounded by exothermic and endothermic reactions. Episode 29 starts by describing the first law of Thermodynamics (1:39) as well as the terms system and surroundings (1:53) using the combustion of hydrogen as an example. We take a closer look at the bond breaking and bond formation of the combustion (2:20) and describe the energy diagrams for exothermic (2:51) and endothermic reactions (4:12). Hand warmers and cooling packs are great examples of exothermic and endothermic processes (4:47). But also purely physical changes, like water freezing or ice melting can be described as exothermic or endothermic (5:31).Question: In Chemistry, we use Enthalpy as a...2021-01-0407 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Listener’s Choice IIOur episode recaps two connected concepts: Boiling points and the strength of intermolecular forces. We start with the chemistry definition of boiling points (0:53) and take a closer look at what happens at the start of heating (1:13), while heating (1:30) and at the boiling point of a pot of water (1:41). The episode then takes a closer look at the connection between atmospheric pressure and boiling point (2:02). For our second topic, we review the five types of intermolecular forces (4:18) and compare three pairs: hexane and pentanol (4:48), methane and hexane (5:00) as well as water and iodine (5:25).Question: If you cook an...2020-12-2107 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Midterm ReviewEpisode 27 reviews Units 1-4 of the AP Chemistry curriculum. Starting off with Unit 1 it gives an overview over counting atoms and isotopes (1:28). Diving deeper, we review atomic structure and electron configurations (2:17) as well as Coulomb’s Law (3:04). In Unit 2 the episode focuses on the types of bonds (3:33) and how they are determined. The second half of the Unit takes a closer look at covalent compounds by describing Lewis Diagrams and VSEPR Theory (5:26). In unit 3 we recap the intermolecular forces (6:05), which lays the foundation for gas laws (7:03) and solutions (7:30). Unit 4 finally gets us to some chemical reactions! It introduces types of...2020-12-1411 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Listener’s Choice 1Our listener’s choice recaps three topics: Ideal Gas Laws, Solubility and Internal Energy.We start by recapping what an ideal gas is compared to a real gas (1:28) and review the equation PV=nRT by describing the relationship between selected variables (2:11). We take a closer look at the relationship between particle number and pressure and review partial pressures (3:02). In our solubility recap we review the polarity of the water molecule (4:55) as well as discuss how polarity and intermolecular forces affect solubility and miscibility (5:22). Our third topic starts by defining internal energy (6:17), how the change is calculated (6:41) and th...2020-12-0709 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - CatalysisEpisode 25 starts with the definition of a catalyst and describes how we can identify the catalyst in a set of elementary steps (1:22). Catalysts work by increasing the number of successful collisions, by providing a pathway with a lower activation energy (2:18) or by providing an intermediate with more favorable orientation (2:50). Catalysts can be homogenous, hence in the same phase, or heterogenous in different phases (4:04). Enzymes are bio-catalysts (5:12).Question: (5:53) Which of the following solid catalysts is most effective?A. Fine powered nickelB. Granular nickelC. inch-long nickelThank you for...2020-11-3006 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Reaction Mechanism and Rate LawDid you know that you can compare a chemical reaction with your daily experience in the lunch line? Episode 24 recaps the reaction mechanism and how it relates to the rate law. It starts with a brief recap of factors affecting the rate of a reaction (1:28). A reaction itself can have several elementary steps that make up the overall reaction (2:00). The rate law of the reaction is determined by the slowest elementary step (3:55). Using a general example, episode 24 shows why you cannot use the overall stoichiometry to determine the rate law (4:18) and why termolecular reactions are rare (5:24).Question: (6:26...2020-11-2307 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Reaction Rate and Rate LawDiamonds are forever, aren’t they? Episode 23 recaps reaction rates and rate laws. We start with the definition of a reaction rate using our stoichiometry sandwiches as an analogy (1:30). Focusing on reactants or products, we can measure the rate of appearance or disappearance (2:20). Using collisions, we discuss the factors that influence the rate of a reaction (3:00): concentration of reactants, the temperature, the surface area, or using a catalyst. Zooming in on the relationship between reaction rate and concentration, the episode recaps rate laws. It describes the setup of a rate law using the proportionality constant and reaction orders (5:19) for a...2020-11-1609 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Types of Chemical ReactionsEpisode 22 starts with a recap of the five types of chemical reactions described in episode 6. But then we are getting in deep! The episode introduces acid-base reactions and defines them as reactions in which protons are being transferred (1:53). Not protons, but electrons are being transferred in redox reactions (3:15). To identify which atom has been oxidized and reduced, we recap oxidation numbers (4:12) and look at the combustion of methane (8:19). Last, but not least, we recap precipitation reactions, compare it to dating and learn about eternal bachelors (9:11).Question: (11:38) Which laboratory technique is often used to determine the concentration of...2020-11-0912 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Dive Deeper: StoichiometryStoichiometry, every chemistry student’s nightmare! But we’ve got you! The episode reviews the mole concept and describes the meaning of coefficients in a balanced chemical equation (1:03). Using sandwiches as an analogy, it shows how to relate the amount of reactants to products (2:42) and uses the same concept for the synthesis of ammonia (5:08). With a second reactant, we recap the concept of limiting and excess reactants for the sandwich (5:50) as well as the production of ammonia (6:24). The episode closes with a recap of how to use molar mass to convert moles to grams (6:58).Question:(8:26) Which day is t...2020-11-0209 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Types of Chemical EquationsWhat IS a chemical reaction? Our episode starts with differentiating between physical (1:08) and chemical changes (1:47). To represent chemical reactions, chemists use three different types of chemical equations: Molecular equations that show neutral compounds (4:50), complete ionic equations that show soluble ionic compounds as free floating ions (5:30) and net ionic equations (NIE) (6:30). NIEs remove the spectator ions and show only the ions that are reacting. Tip: Don’t forget your coefficients! (7:10).Question:(8:17) What type of covalently bonded molecules are often represented in ionic form when dissolved in water?Thank you for listening to The APsolute RecAP: Chemistry Ed...2020-10-2609 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Aqueous SolutionsWater is oh so special, being the star of this episode! Episode 19 starts with a recap of Episode 8 definition of solution components, electrolytes and concentration (1:27). Concentration can also be determined relatively by using particle diagrams (2:35). Another application of particle diagrams is to visualize the interaction between solvent particles and solute particles, for example between water and NaCl (4:27). But what about water and oil? (5:21). The difference in boiling point between components of aqueous solutions can be used to separate them during distillation (6:17).Question: (7:55) If you combine 2 liter of 1M NaCl and 2 liter of 1M KF solutions in a 4...2020-10-1908 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Kinetic Molecular TheoryEpisode 18 starts with a recap of a recap: Reviewing Episode 7 Kinetic Molecular Theory (1:06) and the relationship between pressure, temperature and volume. Taking a closer look at temperature, it connects it to average kinetic energy (2:15), which can be calculated using mass and particle speed. The episode then describes graphs showing Maxwell-Boltzmann distributions of particle speed for different temperatures (2:55) as well as different gases at the same temperature (5:08).Question: (6:27) Which of the following elements shows behavior that is the closest to the ideal gas behavior?A.Helium B.Fluorine C.Oxygen D.XenonThank you...2020-10-1207 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Intermolecular ForcesThis episode recaps the five types of intermolecular forces, discusses factors influencing the strength of force and provides examples. It starts with the weakest IMF, London Dispersion Forces (2:05) and introduces polarizability (2:31). In order of increasing strength we recap dipole-induced dipole interaction (5:00), dipole-dipole interaction (6:55), hydrogen bonding (7:35) and ion-dipole interaction (8:38).Question: (9:30) Which isomer of pentane has the higher boiling point - n-Pentane (C5H12) or neopentane (C(CH3)4)?Thank you for listening to The APsolute RecAP: Chemistry Edition!(AP is a registered trademark of the College Board and is not affiliated with The APsolute RecAP...2020-10-0510 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - VSEPR TheoryIn this episode we define the acronym V-S-E-P-R and take a closer look at bonding and non-bonding electron pairs around a central atom (1:10). We distinguish between electron-domain geometry and molecular geometry (1:50). The episode describes the six electron-domain geometries (2:40) as well as the molecular geometries and bonding angles that arise from “mix and matching” bonding and non-bonding electron pairs (3:45). Balloons are a great tool to visualize these molecular shapes (7:00).Question: (8:06 )What is the molecular shape of NH3? trigonal planar, trigonal pyramidal, or tetrahedralThank you for listening to The APsolute RecAP: Chemistry Edition!(AP is a...2020-09-2808 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Chemical BondsEpisode 15 starts with a quick recap of electronegativity and how it determines the type of bond formed (1:10). Then it takes a closer look at covalent bonds and electronegativity, introducing polar and nonpolar bonds (2:20). Diving even deeper into covalent bonds, we focus on the relationship between distance between nuclei and potential energy and define bond length (5:00). The episode also recaps how the size of bonded atoms and the bond order influence the bond length and bond energy (6:28). Taking a closer look at ionic bonds, we apply Coulomb’s law to determine the strength of interaction between cations and anions (7:27)....2020-09-2110 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Coulomb’s Law and Periodic TrendsThe Periodic Table is trendy! Episode 14 recaps Coulomb’s Law (1:10) and describes how it applies to atomic structure (2:00). We can use Coulomb’s Law to predict atomic radii (3:30) ionic radii (4:00). The episode also defines ionization energy, electronegativity and electron affinity (4:45), describes their periodic trends and ties them to Coulomb’s Law and atomic structure (5:33). But a trend is not always followed. Therefore we also recap two exceptions: the ionization energy of oxygen and nitrogen (6:23) as well as the first ionization energy of boron and beryllium (6:50). And because it is so important, we also have a test taking tip for you (7...2020-09-1409 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Atomic Structure, Electron Configuration and PESThe episode starts with a recap of atomic structure (1:13) before it focuses on electrons. Using Heisenberg’s Uncertainty Principle as a background (2:10) it recaps electron configurations by comparing it to a small town set-up (3:05). We also discuss the Aufbau Principle (5:30) and connect the electron configurations to the periodic table (5:45). Hund’s Rule and Pauli Exclusion Principle are briefly described (7:05). An experimental approach to determine the electron configuration, the photoelectron spectroscopy (7:42), is introduced.Question: What is the German term used for the rule that requires to start the electron configuration at the 1s level? (9:23)Thank you for...2020-09-0710 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Moles, Molar Mass and Mass SpectroscopyThe episode recaps foundational terms for chemical calculations. Starting by comparing the concept of moles to a dozen (:40) we define moles using Avogadro’s number (1:58). Connecting moles to grams we introduce Molar Mass (2:50) and contrast it to atomic mass (3:30). The episode discusses average atomic mass (4:38) and how the abundance of isotopes can be determined utilizing mass spectroscopy (5:25). Using Magnesium as an example the calculations for average atomic mass are described (6:00).Question: What volume does 1 mole of a gas occupy? (7:22)Thank you for listening to The APsolute RecAP: Chemistry Edition!(AP is a registered tr...2020-08-3108 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - AP Overview and Exam StructureWith the goal in mind, we are starting the season to talk about the AP exam! Episode 9 outlines the exam structure with 60 MCQ in 90 minutes (1:25), and seven FRQ questions in 105 minutes (1:55). The course and exam content is based on the CED (2:50). As resources we recommend the AP Classroom (3:50) as well as our podcast (4:40). The episode also gives you some tips for pacing (5:05) and discusses the materials allowed on exam day (5:57).Question: True or false - You can earn partial credit on both the multiple choice and FRQ section of the exam (7:18).Thank you for listening...2020-08-2408 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Big Ideas and Science PracticesTo connect the different concepts throughout the year, we are looking first at the big ideas (0:30): Big idea 1: scale, proportion, and quantity which focuses on the macroscopic as well as atomic scale (1:00). Big idea 2 - structure and properties - connects the atomic makeup of substances with observable properties (1:30). Big idea 3 is all about transformations, die rearrangement of matter (2:14) and big idea 4 connect content related to energy (2:55). In the second part, we are reviewing the six scientific practices that students will have to develop: describing models and representation (4:00), determining scientific questions and methods (4:43), representing data and phenomena (5:34), analyzing and interpreting...2020-08-2409 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Units and ExclusionsThis episode will now discuss the content of the AP Chemistry curriculum by describing the nine units outlined in the CED and their connections. Unit 1 starts with the foundation of atomic structure and properties (1:43). In Unit 2, building on the foundation, students will learn about molecular and ionic compound structure and properties (2:27). Unit 3 then focuses on the intermolecular forces and properties (3:03), which are part of physical changes. In Unit 4 students will learn about chemical changes while being introduced to chemical reactions and stoichiometry (3:52). Unit 5 takes a closer look at the rate of a reaction and the which factors influence it (4:33...2020-08-2409 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Introduction to Solution ChemistryAir and steel are solutions?! Yes! Episode 8 starts by defining solutions (1:30). Using sugar water and salt water it distinguishes between electrolytes and non-electrolytes (2:30). The episode also focuses on factors affecting the solubility like polarity (4:04) and temperature (5:10). Last, but not least, concentration of solutions and how to prepare them is being discussed (6:12).Question: Is milk a solution? (8:42)Thank you for listening to The APsolute RecAP: Chemistry Edition!(AP is a registered trademark of the College Board and is not affiliated with The APsolute RecAP. Copyright 2020 - The APsolute RecAP, LLC. All rights reserved.)2020-08-1709 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Introduction to Gas LawsWhy do you have to measure the cold tire pressure? It all comes down to gases. Episode 7 recaps the Kinetic Molecular Theory (1:22), defines gas variables (2:15), and looks at the relationship between those. Therefore, it recaps Boyle’s Law (3:37), Charles Law (4:36) and Gay-Lussacs Law (5:50).Question: How would an increase in particle number change the pressure within a rigid container? (7:33)Thank you for listening to The APsolute RecAP: Chemistry Edition!(AP is a registered trademark of the College Board and is not affiliated with The APsolute RecAP. Copyright 2020 - The APsolute RecAP, LLC. All rights re...2020-08-1008 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Types of Chemical ReactionsChemistry might seem like magic occasionally, but you don’t need a crystal ball to predict products of reactions! Episode 6 recaps types of chemical reactions and describes how you can identify them. The five types of reactions are: Synthesis (1:29), decomposition (2:34), single displacement (3:33), double displacement (5:00) and combustion (7:29) reaction.Question: Acid-Base reactions are very common in chemistry. Name one of the products of the reaction between HCl and NaOH? (8:44)Thank you for listening to The APsolute RecAP: Chemistry Edition!(AP is a registered trademark of the College Board and is not affiliated with The APsolute Re...2020-08-0309 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Chemical Formulas and NamingBeing able to name chemical compounds can save lives! Therefore, Episode 5 reviews the major naming rules as well as how to write chemical formulas. We start with naming ionic compounds (1:30) and writing the formulas for ionic compounds as formula units (3:00). Then, using greek prefixes we are naming molecular compounds (6:05) and we are discussing the naming of one “special” group of chemical compounds: binary acids (8:00).Question: What is the chemical formula for sulfuric acid? (9:14)Thank you for listening to The APsolute RecAP: Chemistry Edition!(AP is a registered trademark of the College Board and is n...2020-07-2710 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Chemical BondingElements can form different types of chemical bonds to reach noble-gas configuration. Episode 4 recaps three types of chemical bonds. The foundation is laid by the octet rule (1:06). “How” an element reaches the octet is determined by the difference in electronegativity between elements. Electronegativity is the ability of an atom to attract a shared pair of electrons (2:45). This leads to three types of chemical bonding: covalent bonding (4:30), ionic bonding,(5:40) and metallic bonding (7:15).Question: You have two white substances, one ionic, one molecular. Which of the following experimental procedures lets you identify the type of bonding?A. colo...2020-07-2009 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Physical and Chemical ChangeStart your day with a solid breakfast! Episode 1 reviews, compares and contrasts physical and chemical changes and how to recognize them as well as the states of matter. During a physical change a substance retains its identity (1:48) - examples are changes in state: solids, liquids and gas and signs are the change of shape or size (3:24). During chemical changes the identity and properties of substances changes (4:00), which you can observe as color change, heat being released, or bubbles being formed (4:20).Is dissolving salt in water a physical or chemical change? (5:05)Thank you for listening to...2020-07-1305 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Atomic StructureNever trust an atom, they make up everything! But, what is an atom and what is an atom made of? Episode 2 reviews the history of the discovery of the atomic structure. It starts with Democritus who established the term “atom” (1:03), then fast forwards to Dalton, who provided experimental proof for Democritus idea (2:00). J.J. Thomson discovered the electrons (2:35), Ernest Rutherford protons (3:40) and Chadwick neutrons (4:30). The arrangement of these subatomic particles is described by Bohr’s Atomic Model (5:08).Why was it significantly harder to prove the existence of neutrons? (6:22)Thank you for listening to The APsolute RecAP...2020-07-1307 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - Periodic TableBeing able to read the Periodic Table provides you with a “legal cheat sheet”. Therefore, Episode 3 recaps the set-up of the periodic table and how to read it.Dimitri Mendeleev is known as the Father of the Periodic Table (1:25). He arranged the elements with increasing relative atomic mass as well as elements with similar properties together (2:25). Today’s periodic table arranges elements by increasing atomic number (3:13). The horizontal rows in the periodic table are called periods, vertical columns in the periodic table are called families or groups (3:40). Several groups are described in greater detail: alkali metals, alkaline earth...2020-07-1310 minThe APsolute RecAP: Chemistry EditionThe APsolute RecAP: Chemistry Edition - TRAILERThe APsolute RecAP: Chemistry Edition, written by Sarah Rayder and hosted by Melanie Kingett, will be your guide to scoring the five! The APsolute RecAP is designed to maximize your understanding and minimize your need for memorization. Each episode will review content, skills and test taking tips to help you succeed in May.Thank you for listening to The APsolute RecAP: Chemistry Edition!(AP is a registered trademark of the College Board and is not affiliated with The APsolute RecAP. Copyright 2020 - The APsolute RecAP, LLC. All rights reserved.)Website:www...2020-07-0800 min