AP Chemistry: Chapter 1-3 Notes Outline

Objectives:Memorize key ions and atoms symbols and their chargesMatterBe able to count and use significant figures in calculationsBe able to convert measurements using dimensional analysisBe able to name ionic compoundsBe able to name acidsBalance chemical equationsUse dimensional analysis to solve stoichiometric problemsUse dimensional analysis to do limiting reactant problemsUse dimensional analysis to calculate percent yieldCalculate percent compositionCalculate empirical and molecular formulas

Memorize Key ions and atoms: You must score a 95/100 to receive credit. See memory sheet for these items.

Matter:Pure Substances vs Mixtures

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MixturesHomogeneous

Definition

Examples

HeterogeneousDefinition

Examples

Separation of Mixtures

Based on Physical Properties

Distillation

Chromatography

Solubility

Others

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Significant Figures:

Why significant figures?

Rules for counting significant figures1. All nonzero numbers count2. Leading zeros don’t count3. Trailing zeros count if there is a decimal4. Trailing zeros don’t count if there is no decimal

Examples of counting significant figures:

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Rules for calculating with significant figures:1. Addition and Subtraction: You are only as good as your least accurate place value2. Multiplication and Division: You are only as good as your least accurate number of significant figures

Examples of calculations involving significant figures

Convert with Dimensional AnalysisThe principle is that you are multiplying several fractions tog tether, but each is the same measurement so that you are essentially multiplying by 1.

Dimensional Analysis Rules:

1. All numbers must be written as fractions—this includes numbers that are given—so 6.7 grams is

2. All subsequent multipliers are written such that the units must cancel: For example: . Notice how the

grams cancel3. All numbers on the top of a series of fractions are multiplied and all numbers on the bottom of a series of fractions are divided. For

example:

. In your calculator you would: 143.55*0.264*4*2/1000=.

Type 1: One Dimensional Problems

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Type 2 : Working with multiple dimensions—Convert 55 miles per hour into meters per second.

Type 3: Area and Volume: Hint a m3 = m m m

Type 4: Complex Problems

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Naming Ionic CompoundsRules

1. Name Cation2. Use Roman Numerals if the metal is a transition metal (Exceptions: Zn, Ag, Al)3. Name the Anion (It may be a polyion)

Examples: From Name to Formula

Examples: From Formula to Name

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Naming AcidsRules: Always check the anion of the acid

1. If the anion ends in ide change to hydo________ic acid2. If the anion ends in ate change to ________ic acid3. If the anion ends in ite change to ________ous acid4. If the anion is per____ate change to per_____ic acid

Examples

Balance chemical equations

Balance the following:

__C6H12O6 + __O2 __CO2 + __H2O

__H2 + __O2 __H2O

__H2 + __N2 __NH3

__NO + __O2 __NO2

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Stoichiometry Problems using dimensional AnalysisRules

1. Always start with a balanced equation2. Write what you know underneath the chemical that is known (5.23grams)3. Place a question mark (?) underneath what you are looking for.4. Use dimensional analysis to convert to the chemical you are trying to find information about. Note that you will most likely need to

use the mole-mole ratio (also called the stoichiometric ratio) to convert from one chemical to another.

Examples

How many liters of hydrogen gas is formed when 13.5-grams of calcium reacts with sulfuric acid?

Nitrogen gas reacts with oxygen to form dinitrogen trioxide. How many molecules of oxygen are needed to make 5.5 L of N2O3 at STP?

Calcium Carbonate decomposes into calcium oxide and a common gas. When 45.5 grams of calcium oxide is formed how many liters of gas is also formed from this reaction.

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Limiting Reactant ProblemsRules1. Convert all reactants to moles2. Divide by the coefficient in the balanced equation3. The chemical with the lowest number of moles is the limiting reactant (LR)4. Use the LR for all further calculations

Example:

When 114.0 g of iron and 252.7 g of chlorine gas reacts, iron(III) chloride is formed. a. Write a balanced equationb. What is the limiting reactant?c. How many grams of Iron (III) chloride is formedd. How much excess reagent is left over at the end of the experiment?

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33.6 grams of sulfur dioxide reacts with 55.3 grams of water to form sulfurous acid.a. Write a balanced equation.b. What is the limiting reactant?c. How many grams of sulfurous acid will be formed?d. How much excess reagent will remain?

Percent YieldRules

1. Balanced Equation2. Write amount given under the reactant that has a value3. You will be given an amount of product (write this under the product) this is the actual amount produced4. Convert given reactant amount to same product (and units) that was given

5.

Examples: Nitrogen gas reacts with hydrogen gas to make ammonia (NH3). 15.5-L of N2 reacts at STP to make 30-L of ammonia. What is the percentage yield?

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Percent CompositionFind the percentage composition of a chemical by finding the total molar mass of the compound find the mass percent of each element in a compound:

Example: NH4NO3

Percent Error

Empirical Formula:Rules

1. Percent to Mass2. Mass to Moles3. Divide by small4. Times till whole

Example:Determine the empirical formula of a compound with 52.8% Sn, 12.4% Fe, 16% C and 18.8% N.

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Molecular Formulas1. Molecular Formulas are ________ _________not just the simplest _____________2. the molar mass of the empirical formula (EF) is always a multiple of the MW. 3. Use the MW to determine by what factor you need to multiply the empirical formula to find the molecular formula.

Example Determine the molecular formula for a compound that contains 22.5% Na, 30.4% P and 47.1% O and a molar mass of 306 g/mol

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Example: Complex Molecular and Empirical Formula Problems—Combustion Problems Many homes in rural America are heated by propane gas, a compound that contains only carbon and hydrogen. Complete combustion

of a sample of propane produced 2.641 grams of carbon dioxide and 1.442 grams of water as the only products. Find the empirical formula of propane.

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Galactose (Gal) (also called brain sugar) is a type of sugar found in dairy products, in sugar beets and other gums and mucilages. When 2.315 grams of galactos is completely burned it produces 3.953 grams of carbon dioxide and 1.389 grams of water. The molar mass of galactose is between 172 g/mol and 186 g/mol. What is the empirical and molecular formula of galactose?

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: Three volatile compounds X, Y, and Z each contain element Q. The percent by weight of element Q in each compound was determined. Some of the data obtained are given below.Compound Percent by

weight of Element Q

Molecular Weight

X 64.8% ?Y 73.0% 104.Z 59.3% 64.0

(a) The vapor density of compound X at 27˚C and 750. mm Hg was determined to be 3.53 grams per liter. Calculate the molecular weight of compound X.

(b) Determine the mass of element Q contained in 1.00 mole of each of the three compounds.(c) Calculate the most probable value of the atomic weight of element Q.(d) Compound Z contains carbon, hydrogen, and element Q. When 1.00 gram of compound Z is oxidized and all

of the carbon and hydrogen are converted to oxides, 1.37 grams of CO2 and 0.281 gram of water are pro-duced. Determine the most probable molecular formula of compound Z.

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