The APsolute RecAP: Chemistry Edition

Melanie Kingett, Sarah Rayder, Brad Kingett, Zach Caruso

The 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. (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.)

  1. 12/20/2021

    The APsolute RecAP: Chemistry Edition - Episode 59: Unit 6 selected FRQs

    Unit 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) we calculate how much energy 1 mole of 2-propanol would release. Part (c) asks about the effect of having a water/propanol mixture on the final temperature. Question 3 of the 2013 exam starts with stoichiometry - identifying the limiting reactant (5:30) and in part (b) the inconsistent trial. In (c) we are using again mCAT for our calculations. (D) and (e) have us calculate the enthalpy - in d) using experimental data, in (e) as enthalpy of formation. In (f) we are provided with an explanation for the discrepancy between (d) and (e) and are asked to explain if that could be the reason. Today’s Question of the day is about Enthalpy. How do we calculate the enthalpy using bond enthalpies? A. bonds broken - bonds formed B. bonds formed - bonds broken C. bonds broken + bonds formed D. bonds formed + bonds broken 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 2021 - The APsolute RecAP, LLC. All rights reserved.) Website: www.theapsoluterecap.com EMAIL: TheAPsoluteRecAP@gmail.com Follow Us: INSTAGRAM TWITTER FACEBOOK YOUTUBE

    14 min
  2. 12/06/2021

    The APsolute RecAP: Chemistry Edition - Episode 58: Energy of Phase Changes

    We 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 added is used to overcome the intermolecular forces. For these segments we use the enthalpies of fusion and vaporization to calculate the heat added (5:54). The episode closes with three important reminders about the heat of vaporization, the magnitude of enthalpies for a cooling curve and a reminder about the units for the calculations (6:26). Question: Which of the following substances would have the greatest enthalpy of fusion? A. methane (CH4) B. acetic acid (CH3COOH) C. ethanol (C2H5OH) 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 2021 - The APsolute RecAP, LLC. All rights reserved.) Website: www.theapsoluterecap.com EMAIL: TheAPsoluteRecAP@gmail.com Follow Us: INSTAGRAM TWITTER FACEBOOK YOUTUBE

    10 min
  3. 11/22/2021

    The APsolute RecAP: Chemistry Edition - Episode 56: Concentration Changes Over Time

    An 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 and first order k equals - slope and for second order reactions k = slope. (5:03) Integrated rate laws can be used to calculate the concentration after a specific amount of time or to determine how long a reaction has to run to get a specific concentration. A specific application of the rate laws is half-life. In AP Chemistry, half-life is always a first-order reaction. (6:15) Question: If you have a reaction with a half-life of 4 days and an initial concentration of 0.1M, what fraction will be left after 20 days? (8:30) 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 2021 - The APsolute RecAP, LLC. All rights reserved.) Website: www.theapsoluterecap.com EMAIL: TheAPsoluteRecAP@gmail.com Follow Us: INSTAGRAM TWITTER FACEBOOK YOUTUBE

    9 min
  4. 11/15/2021

    The APsolute RecAP: Chemistry Edition - Episode 55: Unit 4 Selected FRQs

    Unit 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 the effect of incomplete oxidation (5:34). Question 1 from 2014 is a gravimetric analysis with the goal of determining the iodide content in a potassium iodide tablet (7:00). Therefore we write the net-ionic equation (7:22), reflect on our data (7:52) and ion concentrations (8:06) before we calculate the number of moles of precipitate (8:23) and percentage iodide (8:53). Part f) concludes with a question about a potential error (9:38). Question: True or false: You MUST indicate the state of matter in parentheses in your balanced chemical equation, even if not asked for it. 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 2021 - The APsolute RecAP, LLC. All rights reserved.) Website: www.theapsoluterecap.com EMAIL: TheAPsoluteRecAP@gmail.com Follow Us: INSTAGRAM TWITTER FACEBOOK YOUTUBE

    12 min
4.8
out of 5
20 Ratings

About

The 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. (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.)