Question 1

Which of the following observations is NOT typically considered evidence that a chemical reaction has occurred?

Accepted Answer

The solution is stirred and the stirring rod dissolves.

Question 2

Which of the following is the correctly balanced equation for the combustion of methane ($$\mathrm{CH_4$}) in $$oxygen?

Accepted Answer

$$\mathrm{CH_4$ + 2O_2 \rightarrow CO_2$ + 2H_2O}$$

Question 3

A student mixes solutions of $$\mathrm{Na_2SO_4}$$ and $$\mathrm{$$BaCl_2$$}. A $$white precipitate forms. According to solubility rules, what is the identity of the precipitate?

Accepted Answer

$$\mathrm{$$BaSO_4$$}$$

Question 4

Which of the following is the correct net ionic equation for the reaction between aqueous solutions of $$\mathrm{$$AgNO_3$$}$$ and $$\mathrm{NaCl}$$?

Accepted Answer

$$\mathrm{Ag^+ (aq) + Cl^- (aq) \rightarrow AgCl (s)}$$

Question 5

Which of the following ions would be considered a spectator ion in the reaction between $$\mathrm{K_2SO_4}$$ and $$\mathrm{Ba(NO_3$)_2} in $$aqueous solution?

Accepted Answer

$$\mathrm{K^+}$$

Question 6

Which of the following best describes a redox reaction?

Accepted Answer

A reaction in which electrons are transferred between species.

Question 7

Which of the following reactions is an example of a gas evolution reaction?

Accepted Answer

$$\mathrm{2HCl (aq) + Na_2CO_3 (aq) \rightarrow 2NaCl (aq) + H_2O (l) + CO_2$ (g)}$$

Question 8

Given the reaction: $$\mathrm{2KI (aq) + Pb(NO_3$)_2 (aq) \rightarrow 2KNO_3 (aq) + $$PbI_2$$ (s)}$$, which of the following is the complete ionic equation?

Accepted Answer

$$\mathrm{2K^+ (aq) + 2I^- (aq) + Pb$$^{2+}$$ (aq) + 2NO_3^- (aq) \rightarrow 2K^+ (aq) + 2NO_3^- (aq) + $$PbI_2$$ (s)}$$

Question 9

Which of the following best describes the role of spectator ions in a chemical reaction?

Accepted Answer

They remain unchanged and do not participate in the net ionic equation.

Question 10

Which of the following is the correct molecular equation for the reaction between $$\mathrm{H_2SO_4}$$ and $$\mathrm{Ba(OH)_2}$$?

Accepted Answer

$$\mathrm{H_2SO_4 (aq) + Ba(OH)_2 (aq) \rightarrow $$BaSO_4$$ (s) + 2H_2O (l)}$$

Question 11

A solution of $$\mathrm{Na_2CO_3} is $$mixed with $$\mathrm{HCl}. $$Which of the following is the net ionic equation for the gas evolution reaction that occurs?

Accepted Answer

$$\mathrm{CO_3$^{2-} (aq) + 2H^+ (aq) \rightarrow H_2O (l) + CO_2$ (g)}$$

Question 12

Which of the following reactions is an example of an acid-base neutralization?

Accepted Answer

$$\mathrm{$$HNO_3$$ (aq) + KOH (aq) \rightarrow $$KNO_3$$ (aq) + H_2O (l)}$$

Question 13

Which of the following best describes a precipitation reaction?

Accepted Answer

A reaction in which an insoluble solid forms when two solutions are mixed.

Question 14

Which of the following is the correct net ionic equation for the reaction between $$\mathrm{HCl}$$ and $$\mathrm{NaOH}$$?

Accepted Answer

$$\mathrm{H^+ (aq) + OH^- (aq) \rightarrow H_2O (l)}$$

Question 15

A student mixes $$\mathrm{$$CaCl_2$$}$$ and $$\mathrm{Na_2CO_3} in $$water. According to solubility rules, what is the precipitate formed?

Accepted Answer

$$\mathrm{$$CaCO_3$$}$$

Question 16

Which of the following is the correct balanced equation for the reaction of aluminum with copper(II) sulfate?

Accepted Answer

$$\mathrm{2Al (s) + 3CuSO_4 (aq) \rightarrow Al_2$(SO_4$)_3 (aq) + 3Cu (s)}$$

Question 17

Which of the following statements about solubility rules is correct?

Accepted Answer

All nitrates ($$\mathrm{NO_3$^-}) $$are soluble in water.

Question 18

Which of the following is the correct net ionic equation for the reaction between $$\mathrm{Ba(NO_3$)_2}$$ and $$\mathrm{Na_2SO_4}$$?

Accepted Answer

$$\mathrm{Ba$$^{2+}$$ (aq) + SO_4$^{2-} (aq) \rightarrow $$BaSO_4$$ (s)}$$

Question 19

A hospital uses the reaction between $$\mathrm{$$CaCl_2$$}$$ and $$\mathrm{Na_2CO_3} to $$remove calcium ions from water. Which ions are spectator ions in this process?

Accepted Answer

$$\mathrm{Na^+}$$ and $$\mathrm{Cl^-}$$

Chemical Reactions: Evidence, Equations, and Types

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