FRQ #1-3: Balancing and Reaction Types

Background

Topic: Chemical Reactions and Equation Balancing

This section tests your ability to identify different types of chemical reactions (such as synthesis, decomposition, single replacement, double replacement, and combustion) and to balance chemical equations according to the law of conservation of mass.

Key Terms and Formulas:

• Law of Conservation of Mass: Matter is neither created nor destroyed in a chemical reaction.

• Balancing Equations: Adjusting coefficients to ensure the same number of each atom on both sides of the equation.

Step-by-Step Guidance

1. Identify the type of reaction (e.g., synthesis, decomposition, etc.).

2. Write the unbalanced chemical equation for the reaction.

3. List the number of atoms of each element on both sides of the equation.

4. Adjust coefficients (not subscripts) to balance the atoms for each element.

Try solving on your own before revealing the answer!

FRQ #4-5: Predicting What Reactions Actually Occur

Background

Topic: Reaction Prediction and Activity Series

This section tests your ability to predict whether a reaction will occur based on reactivity trends, solubility rules, and the activity series of metals.

Key Terms and Formulas:

• Activity Series: A list of elements organized by their reactivity.

• Solubility Rules: Guidelines to predict the formation of precipitates in double replacement reactions.

Step-by-Step Guidance

1. Identify the reactants and the type of reaction (single or double replacement).

2. Use the activity series or solubility rules to determine if a reaction will occur.

3. If a reaction occurs, write the products and balance the equation.

Try solving on your own before revealing the answer!

FRQ #6: Oxidation-Reduction

Background

Topic: Redox Reactions

This section tests your understanding of oxidation states, identifying oxidizing and reducing agents, and balancing redox reactions.

Key Terms and Formulas:

• Oxidation: Loss of electrons (increase in oxidation state).

• Reduction: Gain of electrons (decrease in oxidation state).

• Oxidizing Agent: Substance that is reduced.

• Reducing Agent: Substance that is oxidized.

Step-by-Step Guidance

1. Assign oxidation numbers to all elements in the reaction.

2. Identify which elements are oxidized and which are reduced.

3. Write half-reactions for oxidation and reduction.

4. Balance each half-reaction for mass and charge.

Try solving on your own before revealing the answer!

FRQ #7-11: Writing Formulas, Predicting Products, & Balancing Equations

Background

Topic: Chemical Nomenclature, Reaction Prediction, and Equation Balancing

This section tests your ability to write correct chemical formulas, predict products of reactions, and balance chemical equations.

Key Terms and Formulas:

• Chemical Formula: Representation of a substance using element symbols and subscripts.

• Balancing Equations: Ensuring equal numbers of each atom on both sides.

Step-by-Step Guidance

1. Write correct formulas for all reactants and products.

2. Predict the products based on reaction type.

3. Balance the equation by adjusting coefficients.

Try solving on your own before revealing the answer!

FRQ #12: Particle Representation of Stoichiometry

Background

Topic: Stoichiometry and Particle Diagrams

This section tests your ability to relate balanced chemical equations to particle-level representations (molecules, atoms, ions).

Key Terms and Formulas:

• Stoichiometry: Quantitative relationships in chemical reactions.

• Mole Ratio: Ratio of coefficients from a balanced equation.

Step-by-Step Guidance

1. Interpret the balanced equation in terms of particles (e.g., molecules, atoms).

2. Use mole ratios to relate the number of particles of each substance.

3. Draw or analyze diagrams that represent the stoichiometry of the reaction.

Try solving on your own before revealing the answer!

FRQ #13: Simplest Stoichiometry

Background

Topic: Basic Stoichiometric Calculations

This section tests your ability to use balanced equations to calculate amounts of reactants or products.

Key Terms and Formulas:

• Mole Ratio: Ratio from the balanced equation.

• Stoichiometric Calculation:

Step-by-Step Guidance

1. Convert given quantities to moles if necessary.

2. Use the mole ratio from the balanced equation to find the moles of the desired substance.

3. Convert moles back to grams or other units if required.

Try solving on your own before revealing the answer!

FRQ #14: Gas Stoichiometry and Percent Yield

Background

Topic: Gas Laws and Reaction Yield

This section tests your ability to use the ideal gas law in stoichiometric calculations and to determine percent yield.

Key Terms and Formulas:

• Ideal Gas Law:

• Percent Yield:

Step-by-Step Guidance

1. Use the ideal gas law to find moles of gas if needed.

2. Perform stoichiometric calculations to find theoretical yield.

3. Calculate percent yield using actual and theoretical yields.

Try solving on your own before revealing the answer!

FRQ #15: Solution Stoichiometry and Net Ionic Equations

Background

Topic: Solution Chemistry and Ionic Equations

This section tests your ability to perform stoichiometric calculations with solutions and to write net ionic equations.

Key Terms and Formulas:

• Molarity (M):

• Net Ionic Equation: Shows only the species that actually change during the reaction.

Step-by-Step Guidance

1. Calculate moles of reactants using molarity and volume.

2. Write the balanced molecular equation.

3. Write the complete ionic equation, then cancel spectator ions to get the net ionic equation.

Try solving on your own before revealing the answer!

FRQ #16: Limiting and Excess Reactant

Background

Topic: Limiting Reactant and Excess Calculation

This section tests your ability to identify the limiting reactant in a chemical reaction and calculate the amount of excess reactant remaining.

Key Terms and Formulas:

• Limiting Reactant: The reactant that is completely consumed first, limiting the amount of product formed.

• Excess Reactant: The reactant that remains after the reaction is complete.

Step-by-Step Guidance

1. Convert all given quantities to moles.

2. Use the balanced equation to determine the mole ratio of reactants.

3. Compare the mole ratio to identify the limiting reactant.

4. Calculate the amount of product formed and the amount of excess reactant remaining.

Try solving on your own before revealing the answer!