Question 1

A bottle of antacid liquid contains aluminum hydroxide, Al(OH)$$_3. $$What is the molar mass of aluminum hydroxide?

$$\mathrm{Al(OH)_3}

Al$$: $$1 	imes 26.98 = 26.98
O$$: $$3 	imes 16.00 = 48.00
H$$: $$3 	imes 1.01 = 3.03$$
Total = $$78.01 g/$$mol

Accepted Answer

78.01 g/mol

Question 2

Lithium carbonate (Li$$_2CO$_3) is $$used to treat bipolar disorder. Calculate its molar mass.

Li: $$2 	imes 6.94 = 13.88
C$$: $$1 	imes 12.01 = 12.01
O$$: $$3 	imes 16.00 = 48.00$$
Total = $$73.89 g/$$mol

Accepted Answer

73.89 g/mol

Question 3

How many moles of ammonium chloride (NH$$_4Cl$$, molar mass $$53.50 g/$$mol) are present in $$125 g of $$the compound?

Use: $$\mathrm{mol = \frac{mass}{molar\ mass}}$$

Accepted Answer

2.34 mol

Question 4

Calculate the mass in grams corresponding to $$2.50$$ mol of ethane, C$$_2H$_6 ($$molar mass $$30.08 g/$$mol).

Use: $$\mathrm{mass = mol 	imes molar\ mass}$$

Accepted Answer

75.2 g

Question 5

A box of salt contains $$737 g of $$NaCl. How many moles of NaCl are present? (Molar mass NaCl = $$58.44 g/$$mol)

$$\mathrm{mol = \frac{mass}{molar\ mass}}$$

Accepted Answer

12.6 mol

Question 6

Which of the following is evidence that a chemical reaction has occurred?

Accepted Answer

A color change is observed

Question 7

Given the reaction: $$\mathrm{CaO(s) + H_2O(l) \rightarrow Ca(OH)_2(aq)}$$, what are the reactants and products, and what is the physical state of Ca(OH)$$_2$$?

Accepted Answer

Reactants: CaO(s), H$$_2O(l$$); Product: Ca(OH)$$_2(aq$$); Ca(OH)$$_2 is $$aqueous

Question 8

Which type of reaction is represented by the equation: $$\mathrm{2HgO(s) \xrightarrow{\Delta} 2Hg(l) + O_2$(g)}$$?

Accepted Answer

Decomposition

Question 9

A student weighs $$0.550 g of $$lithium chloride (LiCl, molar mass $$42.39 g/$$mol). How many moles is this?

$$\mathrm{mol = \frac{mass}{molar\ mass}}$$

Accepted Answer

0.0130 mol

Question 10

Calculate the molar mass of glucose, C$$_6H$_{12}O$_6.

C$$: $$6 	imes 12.01 = 72.06
H$$: $$12 	imes 1.01 = 12.12
O$$: $$6 	imes 16.00 = 96.00$$
Total = $$180.18 g/$$mol

Accepted Answer

180.18 g/mol

Question 11

Calculate the mass in grams corresponding to $$0.100$$ mol of glucose (C$$_6H$_{12}O$_6$$, molar mass $$180.18 g/$$mol).

$$\mathrm{mass = mol 	imes molar\ mass}$$

Accepted Answer

18.02 g

Question 12

Which of the following best describes a double-replacement reaction?

Accepted Answer

Two compounds exchange ions to form two new compounds

Question 13

Which equation would you use to convert grams of a substance to moles?

Accepted Answer

$$\mathrm{mol = \frac{mass}{molar\ mass}}$$

Question 14

Which of the following is NOT a sign that a chemical reaction has occurred?

Accepted Answer

The substance is filtered

Question 15

A reaction requires energy to proceed, as indicated by a symbol over the reaction arrow. Which symbol is used?

Accepted Answer

$$\Delta$$

Question 16

Which of the following best describes a combination reaction?

Accepted Answer

Two or more reactants combine to form a single product

Question 17

Which of the following is the correct balanced equation for the decomposition of hydrogen peroxide ($$\mathrm{H_2O_2}) $$into water and oxygen gas?

Accepted Answer

$$2\mathrm{H_2O_2(l)} \rightarrow 2\mathrm{H_2O(l)} + \mathrm{O_2$(g)}$$

Question 18

Which of the following is a correct net ionic equation for the precipitation reaction between aqueous solutions of silver nitrate and sodium chloride?

Accepted Answer

$$\mathrm{Ag^+(aq) + Cl^-(aq) \rightarrow AgCl(s)}$$

Chemical Quantities and Reactions: Study Guide for General Chemistry

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