Question 1

Which of the following is the correctly balanced equation for the decomposition of lead(II) nitrate, $$\mathrm{Pb(NO_3$)_2(s)}$$?

Accepted Answer

$$\mathrm{2\ Pb(NO_3$)_2(s) \rightarrow 2\ Pb(s) + 4\ NO_2$(g) + O_2$(g)}$$

Question 2

What type of reaction is represented by the combustion of pentane: $$\mathrm{C_5H_{12}(g) + O_2$(g) \rightarrow CO_2$(g) + H_2O(l)}$$?

Accepted Answer

Combustion

Question 3

Calculate the formula weight (molar mass) of strontium phosphate, $$\mathrm{Sr_3$(PO_4$)_2}$$, using the following atomic masses: Sr = 87.62, P = 30.97, O = 16.00.

Accepted Answer

$$\mathrm{452.87\ g/mol}$$

Question 4

What is the percent by mass of silver in silver(I) oxide, $$\mathrm{Ag_2O}$$? (Ag = 107.87, O = 16.00)

Accepted Answer

$$\mathrm{93.1\%}$$

Question 5

Given the empirical formula $$\mathrm{C_6H_8O_4N_2}$$, which of the following is a possible molecular formula?

Accepted Answer

$$\mathrm{C$$_{12}$$H_{16}O_8N_4$$}$

Question 6

A compound has an empirical formula of $$\mathrm{C_2H_5ON}$$ and a molar mass of 118 g/mol. What is its molecular formula?

Accepted Answer

$$\mathrm{C_4H_{10}O_2N_2}$$

Question 7

A sample contains 2.00 g of sulfur and 7.13 g of fluorine. What is the empirical formula of the compound formed?

Accepted Answer

$$\mathrm{SF_6$}$$

Question 8

Which of the following best describes the reaction: $$\mathrm{2Al(s) + 3O_2(g) \rightarrow 2Al_2O_3(s)}$$?

Accepted Answer

Synthesis (Combination) reaction

Question 9

If 10.0 g of $$\mathrm{C_5H_{12}} is $$combusted in excess oxygen, how many grams of $$\mathrm{CO_2$}$$ are produced? (Molar masses: $$\mathrm{C_5H_{12}} = 72.15 g/$$mol, $$\mathrm{CO_2$} = 44.01 g/$$mol)

Accepted Answer

$$\mathrm{30.5\ g}$$

Question 10

Which of the following is the correct percent by mass of oxygen in $$\mathrm{Ag_2O}$$? (Ag = 107.87, O = 16.00)

Accepted Answer

$$\mathrm{6.9\%}$$

Question 11

A student claims that the reaction $$\mathrm{2Al(s) + 3O_2(g) \rightarrow 2Al_2O_3(s)} is a $$decomposition reaction. Which argument best refutes this claim?

Accepted Answer

The reaction forms a single product from two reactants, which is characteristic of a synthesis reaction.

Question 12

Which of the following best describes the products of the decomposition of $$\mathrm{Pb(NO_3$)_2}$$?

Accepted Answer

Solid lead, nitrogen dioxide gas, and oxygen gas

Question 13

If 5.00 g of $$\mathrm{Ag_2O} is $$decomposed, how many grams of oxygen gas are produced? (Molar mass $$\mathrm{Ag_2O} = 231.74 g/$$mol)

Accepted Answer

$$\mathrm{0.172\ g}$$

Question 14

Which of the following is the correct molar mass for the empirical formula $$\mathrm{C_2H_5ON}$$? (C = 12.01, H = 1.01, O = 16.00, N = 14.01)

Accepted Answer

$$\mathrm{59.07\ g/mol}$$

Question 15

A real-world application: Silver oxide ($$\mathrm{Ag_2O}) is $$used in button batteries. If a battery contains 0.500 g of $$\mathrm{Ag_2O}$$, how many moles of silver does it contain?

Accepted Answer

$$\mathrm{0.0043\ mol}$$

Question 16

Which of the following is a correct statement about empirical and molecular formulas?

Accepted Answer

The empirical formula represents the simplest whole-number ratio of atoms in a compound, while the molecular formula shows the actual number of atoms of each element in a molecule.

General Chemistry: Balancing Equations, Reaction Types, and Formula Calculations

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