Q: How many grams of $$\mathrm{CO_2$}$$ are produced from the complete combustion of 3.4 $$\times$$ $$10^{15} g of $$octane ($$\mathrm{C_8H_{18}}$$)? (Molar mass $$\mathrm{C_8H_{18}} = 114.22 g/$$mol, $$\mathrm{CO_2$} = 44.01 g/$$mol, $$2 \mathrm{C_8H_{18}} + 25 \mathrm{O_2$} \rightarrow 16 \mathrm{CO_2$} + 18 \mathrm{H_2O})$$

$$2.1 \times 10$$^{16}$$ g$$\ \mathrm{$$CO_2$$}$$

Question 1

Which of the following best describes a chemical change?

Accepted Answer

A process in which atoms rearrange, transforming the original substances into different substances.

Question 2

Which of the following is the correct balanced equation for the combustion of ethane ($$\mathrm{C_2H_6}) in $$oxygen?

Accepted Answer

$$\mathrm{2 C_2H_6(g) + 7 O_2$(g) \rightarrow 4 CO_2$(g) + 6 H_2O(g)}$$

Question 3

A reaction mixture contains 167 g of $$\mathrm{Fe_2O_3}$$ and 85.8 g of CO. If CO is the limiting reactant in the reaction $$\mathrm{Fe_2O_3(s) + 3 CO(g) \rightarrow 2 Fe(s) + 3 CO_2$(g)}$$, what is the mass of $$\mathrm{Fe_2O_3}$$ left over after the reaction goes to completion? (Molar masses: $$\mathrm{Fe_2O_3} = 159.7 g/$$mol, CO = 28.01 g/mol)

Accepted Answer

111 g

Question 4

Which of the following statements about the law of conservation of mass is correct?

Accepted Answer

The total mass of reactants equals the total mass of products in a chemical reaction.

Question 5

In the reaction $$\mathrm{2 K(s) + Br_2$(g) \rightarrow 2 KBr(s)}$$, what type of reaction is this and what is the oxidation state of potassium in the product?

Accepted Answer

Synthesis; +1

Question 6

How many grams of $$\mathrm{CO_2$}$$ are produced from the complete combustion of 3.4 $$	imes$$ $$10^{15} g of $$octane ($$\mathrm{C_8H_{18}}$$)? (Molar mass $$\mathrm{C_8H_{18}} = 114.22 g/$$mol, $$\mathrm{CO_2$} = 44.01 g/$$mol, $$2 \mathrm{C_8H_{18}} + 25 \mathrm{O_2$} ightarrow 16 \mathrm{CO_2$} + 18 \mathrm{H_2O})$$

Accepted Answer

$$2.1 	imes 10$$^{16}$$ g$$\ \mathrm{$$CO_2$$}$$

Question 7

Which of the following is the correct sequence of steps to determine the limiting reactant in a chemical reaction?

Accepted Answer

Convert all reactant masses to moles, use stoichiometry to find the maximum product from each, the reactant that produces the least product is limiting.

Question 8

A student mixes 9.05 g of $$\mathrm{NH_3$}$$ with 45.2 g of $$\mathrm{CuO} in $$the reaction $$2 \mathrm{NH_3$(g)} + 3 \mathrm{CuO(s)} \rightarrow \mathrm{N_2$(g)} + 3 \mathrm{Cu(s)} + 3 \mathrm{H_2O(l)}. $$What is the theoretical yield of $$\mathrm{N_2$} in $$grams? (Molar masses: $$\mathrm{NH_3$} = 17.03 g/$$mol, $$\mathrm{CuO} = 79.55 g/$$mol, $$\mathrm{N_2$} = 28.02 g/$$mol)

Accepted Answer

6.65 g

Question 9

Which of the following best describes a combustion reaction?

Accepted Answer

A reaction in which a substance reacts with oxygen to form one or more oxygen-containing compounds, usually releasing heat.

Question 10

What is the percent yield if 42.8 kg of Ti is obtained when 88.2 kg of $$\mathrm{$$TiO_2$$}$$ reacts with 28.6 kg of C, and the theoretical yield is 52.9 kg? Use the equation $$\mathrm{$$TiO_2$$(s) + 2 C(s) \rightarrow Ti(s) + 2 CO(g)}.$$

Accepted Answer

80.9%

Question 11

Which of the following is a correct balanced equation for the reaction between aqueous lead(II) nitrate and aqueous potassium chloride to form solid lead(II) chloride and aqueous potassium nitrate?

Accepted Answer

$$\mathrm{Pb(NO_3$)_2(aq) + 2 KCl(aq) \rightarrow $$PbCl_2$$(s) + 2 $$KNO_3$$(aq)}$$

Question 12

Which of the following is the correct stoichiometric ratio for the reaction $$2 \mathrm{C_8H_{18}(l)} + 25 \mathrm{O_2$(g)} \rightarrow 16 \mathrm{CO_2$(g)} + 18 \mathrm{H_2O(g)}$$?

Accepted Answer

2 mol $$\mathrm{C_8H_{18}}$$ : 25 mol $$\mathrm{O_2$}$$ : 16 mol $$\mathrm{CO_2$}$$ : 18 mol $$\mathrm{H_2O}$$

Question 13

Which of the following is a physical change?

Accepted Answer

Boiling of water

Question 14

What is the correct balanced equation for the reaction between aluminum metal and chlorine gas?

Accepted Answer

$$\mathrm{2 Al(s) + 3 Cl_2$(g) \rightarrow 2 $$AlCl_3$$(s)}$$

Question 15

If 5 molecules of $$\mathrm{CH_4$}$$ and 8 molecules of $$\mathrm{O_2$}$$ are mixed, which is the limiting reactant in the reaction $$\mathrm{CH_4$(g) + 2 O_2$(g) \rightarrow CO_2$(g) + 2 H_2O(g)}$$?

Accepted Answer

$$\mathrm{O_2$}$$

Question 16

Which of the following is the correct balanced equation for the reaction between rubidium metal and water?

Accepted Answer

$$\mathrm{2 Rb(s) + 2 H_2O(l) \rightarrow 2 Rb^+(aq) + 2 OH^-(aq) + H_2$(g)}$$

Question 17

Which of the following best describes the role of a limiting reactant in a chemical reaction?

Accepted Answer

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

Chapter 7: Chemical Reactions and Chemical Quantities – Study Notes

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