Q: What is the percent yield if 42.8 kg of titanium is produced when 28.6 kg of carbon reacts with 88.2 kg of titanium dioxide according to $$\mathrm{$$TiO_2$$(s) + 2\ C(s) \rightarrow Ti(s) + 2\ CO(g)}$$, and the theoretical yield is 53.3 kg?

$$\frac{42.8}{53.3} \times 100\% = 80.3\%$$

Question 1

Which of the following best describes the role of greenhouse gases in Earth's atmosphere, as illustrated in the provided diagram?

Accepted Answer

They allow visible light to pass through and warm Earth's surface, but trap some of the heat radiated from Earth's surface.

Question 2

Based on the graph showing atmospheric carbon dioxide concentration from 1860 to 2020, what trend is observed and what is its likely impact on global temperature?

Accepted Answer

CO2 concentration has increased significantly, which is likely to cause an increase in global temperature.

Question 3

Which chemical equation represents the combustion of butane ($$\mathrm{C_4H_{10}}) $$with oxygen to form carbon dioxide and water?

Accepted Answer

$$\mathrm{2\ C_4H_{10}(g) + 13\ O_2$(g) \rightarrow 8\ CO_2$(g) + 10\ H_2O(g)}$$

Question 4

A plant consumes 37.8 g of $$\mathrm{CO_2$} in $$one week. Using the photosynthesis equation $$6\ CO_2$(g) + 6\ H_2O(l) \xrightarrow{sunlight} 6\ O_2$(g) + C_6H_{12}O_6$(aq)$$, what mass of glucose ($$\mathrm{C_6H_{12}O_6$}) $$can the plant synthesize?

Accepted Answer

25.8 g

Question 5

Which reactant is limiting when 2 mol of nitrogen gas reacts with 8 mol of hydrogen gas to form ammonia ($$\mathrm{NH_3$}) $$according to $$\mathrm{N_2$ + 3\ H_2$ \rightarrow 2\ NH_3$}$$, and how many mol of excess reactant remain after the reaction?

Accepted Answer

Nitrogen is limiting; 2 mol of hydrogen remain.

Question 6

What is the theoretical yield of ammonia in grams when 86.3 g of $$\mathrm{NO}$$ and 25.6 g of $$\mathrm{H_2$}$$ react according to $$2\ NO(g) + 5\ H_2$(g) \rightarrow 2\ NH_3$(g) + 2\ H_2O(g)$$?

Accepted Answer

29.6 g

Question 7

Which of the following statements about balancing chemical equations is correct?

Accepted Answer

You must change the coefficients in front of chemical formulas to balance the equation.

Question 8

If 4 mol of sodium reacts with 1 mol of oxygen to form 2 mol of sodium oxide ($$\mathrm{Na_2O}$$), how many mol of sodium are required to react completely with 3 mol of oxygen?

Accepted Answer

12 mol

Question 9

What is the percent yield if 42.8 kg of titanium is produced when 28.6 kg of carbon reacts with 88.2 kg of titanium dioxide according to $$\mathrm{$$TiO_2$$(s) + 2\ C(s) \rightarrow Ti(s) + 2\ CO(g)}$$, and the theoretical yield is 53.3 kg?

Accepted Answer

$$\frac{42.8}{53.3} 	imes 100\% = 80.3\%$$

Question 10

Which equation correctly represents the reaction between potassium metal and bromine gas?

Accepted Answer

$$\mathrm{2\ K(s) + Br_2$(g) \rightarrow 2\ KBr(s)}$$

Question 11

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

Accepted Answer

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

Question 12

Which of the following best explains why the actual yield of a chemical reaction is usually less than the theoretical yield?

Accepted Answer

Some product is lost to side reactions or does not form during the reaction.

Question 13

Which equation represents the reaction between aqueous strontium chloride and aqueous lithium phosphate to form solid strontium phosphate and aqueous lithium chloride?

Accepted Answer

$$\mathrm{3\ $$SrCl_2$$(aq) + 2\ Li_3PO_4(aq) \rightarrow Sr_3$(PO_4$)_2(s) + 6\ LiCl(aq)}$$

Question 14

If 5 mol of $$\mathrm{NO_2$}$$ and 1 mol of $$\mathrm{H_2O}$$ react completely according to $$3\ NO_2$(g) + H_2O(l) \rightarrow 2\ $$HNO_3$$(l) + NO(g)$$, how many moles of the reactant in excess are present after the reaction?

Accepted Answer

2 mol $$\mathrm{NO_2$}$$ remain.

Question 15

Which of the following is a correct balanced equation for the reaction between solid silicon dioxide and solid carbon to produce solid silicon carbide and carbon monoxide gas?

Accepted Answer

$$\mathrm{$$SiO_2$$(s) + 3\ C(s) \rightarrow SiC(s) + 2\ CO(g)}$$

Question 16

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

Accepted Answer

The reactant that is completely consumed and limits the amount of product formed.

Question 17

Which equation represents the reaction between magnesium hydroxide and hydrochloric acid?

Accepted Answer

$$\mathrm{Mg(OH)_2(aq) + 2\ HCl(aq) \rightarrow 2\ H_2O(l) + $$MgCl_2$$(aq)}$$

Question 18

Which of the following is a correct balanced equation for the combustion of liquid methyl alcohol ($$\mathrm{CH_3OH}$$)?

Accepted Answer

$$\mathrm{2\ CH_3OH(l) + 3\ O_2$(g) \rightarrow 2\ CO_2$(g) + 4\ H_2O(g)}$$

Chemical Reactions and Chemical Quantities: Chapter 4 Study Guide

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