Q: How many hydrogen atoms are in 24.68 grams of ammonia ($$\mathrm{NH_3$}$$)?

$$2.622 \times 10$$^{24}$$ H atoms

Question 1

Balance the following equation: $$\mathrm{C_5H_{10}O_2$ + O_2$ \rightarrow CO_2$ + H_2O}. $$How many carbon atoms are present on the reactant side?

Accepted Answer

5

Question 2

When aluminum hydroxide reacts with sulfuric acid to form aluminum sulfate and water, how many total oxygen atoms are on the products side of the balanced equation?

Accepted Answer

18

Question 3

Which of the following reactions is NOT a combination reaction?

Accepted Answer

$$\mathrm{2Al + 6HCl \rightarrow 3H_2 + 2AlCl_3}$$

Question 4

Which of the following equations represents a decomposition reaction?

Accepted Answer

$$\mathrm{NH_4Cl \rightarrow NH_3$ + HCl}$$

Question 5

What is the molar mass of calcium acetate ($$\mathrm{Ca(C_2H_3O_2)_2}$$)?

Accepted Answer

158 g/mol

Question 6

What is the molar mass of ammonium sulfate ($$\mathrm{(NH_4$)_2SO_4}$$)?

Accepted Answer

132 g/mol

Question 7

When the equation $$\mathrm{C_8H_{18} + O_2$ \rightarrow CO_2$ + H_2O} is $$balanced, what are the coefficients?

Accepted Answer

2, 25, 16, 18

Question 8

How many hydrogen atoms are in 24.68 grams of ammonia ($$\mathrm{NH_3$}$$)?

Accepted Answer

$$2.622 	imes 10$$^{24}$$ H atoms

Question 9

A compound contains 3.407 moles of carbon, 4.54 moles of hydrogen, and 3.406 moles of oxygen. What is its empirical formula?

Accepted Answer

C3H4O3

Question 10

A compound is 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is its empirical formula?

Accepted Answer

CH2O

Question 11

If the molar mass of a compound with empirical formula CH3N is 116 g/mol, what is its molecular formula?

Accepted Answer

C4H12N4

Question 12

In the reaction $$\mathrm{O_3$ + 2NaI + H_2O \rightarrow O_2$ + I_2$ + 2NaOH}$$, 3.5 moles of $$\mathrm{O_3$}$$, 4.0 moles of $$\mathrm{NaI}$$, and 1.5 moles of $$\mathrm{H_2O}$$ are mixed. What is the limiting reactant?

Accepted Answer

H2O

Question 13

Using the reaction $$\mathrm{O_3$ + 2NaI + H_2O \rightarrow O_2$ + I_2$ + 2NaOH}$$ and the limiting reactant from the previous question, how many grams of $$\mathrm{I_2$}$$ are formed?

Accepted Answer

381 g I2

Question 14

5.0 moles of lithium hydroxide and 4.0 moles of carbon dioxide react to form lithium carbonate and water. What mass of the excess reactant is left over after the reaction is complete?

Accepted Answer

66 g

Question 15

In the reaction $$\mathrm{4NH_3 + 5O_2 \rightarrow 4NO + 6H_2O}$$, how many grams of water can be formed from 4.00 grams of $$\mathrm{NH_3$}$$ and 5.0 grams of $$\mathrm{O_2$}$$?

Accepted Answer

3.375 g H2O

Question 16

How many moles of iron(III) chloride can be formed from 3.5 moles of iron and 2.5 moles of chlorine in a combination reaction?

Accepted Answer

2.50 moles

Question 17

How many grams of lithium nitride can be formed when 3.5 grams of lithium and 2.5 grams of nitrogen are reacted in a combination reaction?

Accepted Answer

5.83 grams

Question 18

For the reaction in the previous question, if the actual yield is 3.52 grams, what is the percent yield?

Accepted Answer

60.4%

Question 19

How many grams of $$\mathrm{K_2O}$$ are needed to react with excess water to form 4.50 grams of potassium hydroxide ($$\mathrm{KOH}$$), assuming a yield of 100%?

Accepted Answer

3.78 grams

General Chemistry Chapter 3 Practice Exam – Step-by-Step Study Guidance

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