Question 1

When methane ($$CH_4) $$combusts in a Bunsen burner, what is the correct coefficient in front of $$O_2 in $$the balanced equation for the combustion of one mole of methane?

$$CH_4$$ + $$O_2$$ \rightarrow $$CO_2 + H_2O$

Accepted Answer

$$2$$

Question 2

For the combustion of one mole of butane ($$C_4H_{10}$$), what is the correct coefficient in front of $$O_2 in $$the balanced equation?

$$C_4H_{10} + O_2$ \rightarrow CO_2$ + H_2O$$

Accepted Answer

$$\frac{13}{2}$$

Question 3

Given the balanced equation for the reaction of aluminum with hydrochloric acid:

$$2Al(s) + 6HCl(aq) \rightarrow 2AlCl_3(aq) + 3H_2(g)$$

Which statement below is FALSE?

Accepted Answer

For every mole of $$H_2$$ produced, $$\frac{3}{2}$$ moles of Al are consumed.

Question 4

Which of the following reactions produces the most $$H_2$$ gas per gram of metal reactant?

Accepted Answer

$$2K(s) + 2H_2O(l) \rightarrow 2KOH(aq) + H_2$(g)$$

Question 5

A solution which was initially 8 molar in NaCl was diluted according to the diagram to the right. What is the final concentration of the solution?

Accepted Answer

$$1$$~molar

Question 6

A solution which was initially 4 molar in HCl was diluted according to the diagram to the right. What is the final concentration of the solution?

Accepted Answer

$$0.5$$~molar

Question 7

An Olympic ice hockey team consists of 7 defensemen, 13 forwards, and 2 goalies. If there are 36 goalies, 119 defensemen, and 228 forwards available, what is the maximum number of teams that can be formed and which position is the limiting reagent?

Accepted Answer

17 teams, LR = goalies

Question 8

Consider the reaction: $$Mg(s) + Br_2$(l) \rightarrow $$MgBr_2$$(s). If 1 $$mole of magnesium reacts with 0.06 moles of $$Br_2$$, how many moles of $$MgBr_2$$ will form?

Accepted Answer

$$0.06$$~moles

Question 9

Consider the reaction: $$Mg(s) + Br_2$(l) \rightarrow $$MgBr_2$$(s). If 0.06 $$moles of magnesium react with 0.1 moles of $$Br_2$$, how many moles of $$MgBr_2$$ will form?

Accepted Answer

$$0.06$$~moles

Question 10

1 mole of Cu is added to a solution containing 4 moles of $$HNO_3$$ and reacts according to:

$$3Cu(s) + 8HNO_3(aq) \rightarrow 3Cu(NO_3$)_2(aq) + 4H_2O(l) + 2NO(g)$$

What is the limiting reactant and how many moles of NO could be produced?

Accepted Answer

LR = Cu, $$\frac{2}{3}$$ moles of NO

Question 11

Ammonia is prepared by reacting hydrogen and nitrogen:

$$3H_2(g) + N_2$(g) \rightarrow 2NH_3(g)

If a $$mixture contains 6 molecules of $$H_2$$ and 2 molecules of $$N_2$$, how many molecules of $$NH_3$$ will be formed after the reaction is complete?

Accepted Answer

4 molecules of $$NH_3$$

Question 12

Which of the following is the balanced chemical equation for the decomposition of nitroglycerine ($$C_3H_5N_3O_9$$)?

Accepted Answer

$$4C_3H_5N_3O_9(l) \rightarrow 6N_2(g) + 12CO_2(g) + O_2$(g) + 10H_2O(g)$$

Question 13

After complete combustion of a sample of carbon, the products are $$CO_2$$ and $$H_2O. If $$the products contain 0.5 moles of $$CO_2$$, how many moles of carbon were present initially?

Accepted Answer

$$0.5$$~moles

Question 14

A cyclic hydrocarbon undergoes complete combustion to produce $$CO_2$$ and $$H_2O. If $$the products contain 1 mole of $$CO_2$$ and 1 mole of $$H_2O$$, what was the original hydrocarbon and how many moles were present?

Accepted Answer

Cyclopropane, $$1$$~mole

Question 15

Which statement best describes the concept of limiting reagent in a chemical reaction?

Accepted Answer

It is the reactant that determines the maximum amount of product formed.

Question 16

In the reaction $$2Al(s) + 6HCl(aq) \rightarrow 2AlCl_3(aq) + 3H_2(g)$$, how many moles of $$H_2$$ are produced when 4 moles of $$Al$$ react with excess $$HCl$$?

Accepted Answer

$$6$$~moles

Question 17

If 0.5 moles of $$C_4H_{10}$$ combust completely, how many moles of $$CO_2$$ are produced?

$$2C_4H_{10} + 13O_2 \rightarrow 8CO_2 + 10H_2O$$

Accepted Answer

$$2$$~moles

Chapter 4: Chemical Reactions – Stoichiometry and Balancing Equations

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