AP Chemistry Summer Packet 2021

Name: ______________________________________________

AP Chemistry Summer Packet 2021

Welcome to AP Chemistry!

This summer packet is to help you review important concepts that will allow you to hit the ground running in the fall.

All the answers to the questions in this packet are in the accompanying answer packet. You should read the included summary information for the topics and work the problems as needed to master the skills. It is best to not look at the answers until after you work through a few problems of each type.

You do not need to work every problem. You will be graded on completion only for the summer work. But we will have a quiz during the first week of class to check your mastery of these topics.

It will be very helpful for you to also read through the first three chapters of our textbook (Brown and LeMay). You can find the text book online at the following site:

(Brown_et_al.)

Section 1: Significant Figures

All measurements contain some error. Precision is how closely individual measurements agree with each other. It is a function of the measuring device. The smaller the smallest divisions on a measuring tool, the more precise the measurement. A ruler with millimeter divisions is more precise than a ruler with only centimeter divisions. A balance that measures to three decimal places (milligram) is more precise than one that measures to two decimal places (centigram). Significant figures allow the level of precision of a measurement, and of calculations using a measurement, to be accurately represented. At least one short answer question on the AP exam will score you on your use of correct significant figures. It is very important that you get in the habit of using the correct number of significant figures in your calculations.

Section 2: The Metric System

The metric system (specifically, the SI system, which is a subset of the metric system, though chemistry makes frequent use volume and pressure units that are not SI), is the accepted system of units among scientists. It is essential that you are comfortable with using the metric system. You must master the prefixes, particularly kilo-, centi-, milli-, and micro-.

Section 3: Chemical Formulas

Chemical nomenclature is no longer emphasized on the AP Chemistry exam; however, you are expected to know the names and symbols of common chemical elements. (The periodic table provided with the exam has symbols only.) You are also expected to know the charges of the monoatomic ions of the alkali and alkaline earth metals, and the nonmetals.

Additionally, it is very important be able to quickly recognize what type of compound a substance is from its chemical formula. You will need to be able to do this in order to be able to explain its physical and chemical properties, or to be able to predict the products of a reaction. Recognizing the formulas of common polyatomic ions is essential to this skill, though you do not need to memorize their names.

Section 4: Balancing Equations and Reaction Types

Just like recognizing compounds, balancing equations and recognizing common reaction types are foundational skills. Mastery of these skills will enable you to more easily tackle complex problems. Plus, balancing equations is just fun.

Section 5: Oxidation Numbers

Oxidation numbers are a way of keeping track of electrons in chemical reactions. Being able to assign oxidation numbers to atoms in compounds allows you to recognize redox reactions and track how electrons are transferred in these reactions

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Section 6: Moles The mole is central to quantitative chemistry. It allows us to connect the macroscopic world we see and can measure to the microscopic world of atoms and compounds. You will review key methods of converting macroscopic measurements to quantities of microscopic atoms and compounds. Section 7: Stoichiometry Stoichiometry is the calculation of the quantities of products and reactants using chemical equations. Stoichiometry calculations are central to the practical study and application of chemistry. Stoichiometry problems will permeate nearly every unit of study in AP chemistry. It is imperative that you take the time to understand the why behind each mathematical step you take in a stoichiometry problem. Simply memorizing steps will not be enough. Understanding the why behind chemical calculations will allow you to adapt your skills to new problems.

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Section 1: Significant Figures

Significant figures rules: counting Suppose we what to determine the number of significant digits in the following measurement. In this method a "dot" is the decimal point. Example: 0.001230400 Step 1 - Draw a box around all nonzero digits, beginning with the leftmost nonzero digit and ending with the rightmost nonzero digit in the number, including any sandwiched zeros.

0.001230400

Step 2 - If a dot is present, draw a box around any trailing zeros.

0.0012304 00

Step 3 - All the boxed digits are significant. There are 7 significant digits

A. Indicate the number of significant figures then round each to the number of significant figures indicated. For example: 1.234 has __4___ significant figures and, rounded to 2 significant figures, is ___1.2____

1. 0.6034 has ______ significant figures and, rounded to 2 significant figures, is __________

2. 12,700 has ______ significant figures and, rounded to 2 significant figures, is __________

3. 12,700.00 has ______ significant figures and, rounded to 1 significant figures, is __________

4. 0.000983 has ______ significant figures and, rounded to 2 significant figures, is __________

5. 123342.9 has ______ significant figures and, rounded to 5 significant figures, is __________

6. 6.023 x 1023 has ______ significant figures and, rounded to 2 significant figures, is _________

7. 0.005600 has ______ significant figures and, rounded to 1 significant figures, is __________

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8. 10000.5006 has ______ significant figures and, rounded to 5 significant figures, is _________ 9. 2.0 x 10-3 has ______ significant figures and, rounded to 1 significant figures, is __________ 10. 3.456110 has ______ significant figures and, rounded to 3 significant figures, is __________

Significant figures rules: calculations 1. Addition and subtraction: Limited by the number with the smallest number of decimal places E.g.: 2.01 +5.2 = 7.2 2. Multiplication and division Answer has the same number of sig figs as the number with the fewest digits E.g.: 6.00 ? 2.0 = 12 3. Logarithms (important when we do pH) The number of decimal places in a log (in scientific notation) is equal to the number of sig figs in the original number E.g.: [H+] = 1.0 ? 10-5 pH = 5.00; pH = 2.650 [H+] = 2.24 ? 10-3

B. Given calculations with the calculator answer, write the answers with the appropriate number of significant figures.

Example:

6.00 x 3.00 = 18

The answer should be

______18.0_____

1. 23 + 46

= 69

The answer should be _______________

2. 23.0 + 46.0 = 69

The answer should be _______________

3. 253 + 345.8 = 598.8

The answer should be _______________

4. 56 ? 35

= 21

The answer should be _______________

5. 56.00 ? 35.0 = 21

The answer should be _______________

6. 46 x 12

= 552

The answer should be _______________

7. 3.24 x 5.63 = 18.2412

The answer should be _______________

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