AP Chemistry

Multiple Choice

The reaction between aqueous strontium chloride (SrCl₂) and aqueous potassium sulfate (K₂SO₄) forms a precipitate of strontium sulfate (SrSO₄). Which of the following represents the net ionic equation for the reaction?

• Cl⁻(aq) + K(aq) → KCl(aq)

• Sr²⁺(aq) + SO₄²(aq) → SrSO₄(s)

• Sr²⁺(aq) + 2Cl(aq) + SO₄²⁻(aq) + 2K⁺(aq) → SrSO₄(s) + 2Cl⁻(aq) + 2K⁺(aq)

• SrCl₂(aq) + K₂SO₄(aq) → SrSO₄(s) + 2KCl(aq)

Multiple Choice

...C₃H₈(g) + ...O₂(g) → ...H₂O(g) + ...CO₂(g)

When the equation for the reaction represented above is balanced and all coefficients are reduced to the lowest whole-number terms, the coefficient for O₂(g) is

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• 3

• 5

Multiple Choice

A mixture of CO(g) and O₂(g) is placed in a container, as shown above. A reaction occurs, forming CO₂(g). Which of the following best represents the contents of the box after the reaction has proceeded as completely as possible?

Multiple Choice

Which of the following describes the changes in forces of attraction that occur as H₂O changes phase from a liquid to a vapor?

• H – O bonds break as H – H and O – O bonds form.

• Hydrogen bonds between H₂O molecules are broken.

• Covalent bonds between H₂O molecules are broken.

• Ionic bonds between H⁺ ions and OH^- ions are broken.

Multiple Choice

2 N₂H₄(g) + N₂O₄(g) → 3 N₂(g) + 4 H₂O(g)

When 8.0 g of N₂H₄ (32 g mol^-1) and 92 g of N₂O₄ (92 g mol^-1) are mixed together and react according to the equation above, what is the maximum mass of H₂O that can be produced?

• 9.0 g

• 18 g

• 32 g

• 76 g

Multiple Choice

If it requires 20.0 mL of 1.0 M NaOH to reach the equivalence point of a titration with 10.0 mL of HCl. What is the concentration of the HCl?

• 1.0 M

• 2.0 M

• 0.5 M

• 2.5 M

Multiple Choice

Which of the following correctly identifies a Brønsted-Lowry conjugate acid-base pair in a solution prepared by mixing together HNO₂(aq) and NH₃(aq) ?

• The acid is HNO₂(aq), and the conjugate base is NH₃(aq).

• The acid is HNO₂(aq), and the conjugate base is NO₂⁻(aq).

• The acid is NH₄⁺(aq), and the conjugate base is NO₂⁻(aq).

• The acid is NH₃(aq), and the conjugate base is NH₄⁺(aq).

Multiple Choice

H₂Se(g) + 4 O₂F₂(g) → SeF₆(g) + 2 HF(g) + 4 O₂(g)

Which of the following is true regarding the reaction represented above?

• The oxidation number of O does not change.

• The oxidation number of H changes from -1 to +1.

• The oxidation number of F changes from +1 to -1.

• The oxidation number of Se changes from -2 to +6.

Multiple Choice

Al(s)→Al3+(aq)+3e−

Zn2+(aq)+2e−→Zn(s)

The half-reactions for the oxidation-reduction reaction between Al(s) and Zn2+(aq) are represented above. Based on the half-reactions, what is the coefficient for Al(s) if the equation for the oxidation-reduction reaction is balanced with the smallest whole-number coefficients?

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