Question 1

Which of the following is the correct formula for the compound formed between magnesium and nitrate ions?

Accepted Answer

$$\mathrm{Mg(NO_3$)_2}$$

Question 2

A sample contains 0.5 moles of $$\mathrm{Na_2SO_4}. $$How many sodium atoms are present in the sample?

Accepted Answer

$$1.51 	imes 10$$^{24}$$

Question 3

Which of the following ions has a charge of $$-2$$?

Accepted Answer

$$\mathrm{SO_4$^{2-}}$$

Question 4

What is the empirical formula for a compound containing 40% carbon, 6.7% hydrogen, and 53.3% oxygen by mass?

Accepted Answer

$$\mathrm{CH_2O}$$

Question 5

Which of the following compounds contains a polyatomic ion?

Accepted Answer

$$\mathrm{$$KNO_3$$}$$

Question 6

Calculate the molar mass of $$\mathrm{Ca_3$(PO_4$)_2}.$$

Accepted Answer

$$262 \ \mathrm{g/mol}$$

Question 7

Which of the following is the correct name for $$\mathrm{Fe_2O_3}$$?

Accepted Answer

Iron(III) oxide

Question 8

How many moles are present in $$18 \ \mathrm{g} of $$water ($$\mathrm{H_2O}$$)?

Accepted Answer

$$1.0 \ \mathrm{mol}$$

Question 9

Which of the following formulas represents a compound containing both a metal and a nonmetal?

Accepted Answer

$$\mathrm{Na_2SO_4}$$

Question 10

A compound contains $$27.3 \%$$ carbon and $$72.7 \%$$ oxygen by mass. What is its empirical formula?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 11

What is the oxidation number of sulfur in $$\mathrm{SO_4$^{2-}}$$?

Accepted Answer

$$+6$$

Question 12

Which of the following is the correct formula for ammonium phosphate?

Accepted Answer

$$\mathrm{(NH_4$)_3PO_4}$$

Question 13

How many molecules are present in $$0.25$$ moles of $$\mathrm{CO_2$}$$?

Accepted Answer

$$1.51 	imes 10$$^{23}$$

Question 14

Which of the following is a correct formula for a compound containing a transition metal with variable charge?

Accepted Answer

$$\mathrm{$$FeCl_2$$}$$

Question 15

What is the percent composition by mass of oxygen in $$\mathrm{H_2SO_4}$$?

Accepted Answer

$$65.3\%$$

Question 16

Which of the following is the correct formula for calcium hydroxide?

Accepted Answer

$$\mathrm{Ca(OH)_2}$$

Question 17

A student dissolves $$5.0 \ \mathrm{g} of$$ $$\mathrm{NaCl} in $$water. How many moles of $$\mathrm{NaCl}$$ are present?

Accepted Answer

$$0.086 \ \mathrm{mol}$$

Question 18

Which of the following is the correct formula for the compound formed between aluminum and sulfate ions?

Accepted Answer

$$\mathrm{Al_2$(SO_4$)_3}$$

Question 19

What is the molar mass of $$\mathrm{C_2H_5OH} ($$ethanol)?

Accepted Answer

$$46 \ \mathrm{g/mol}$$

Question 20

Which of the following is the correct formula for the acid formed from the nitrate ion?

Accepted Answer

$$\mathrm{$$HNO_3$$}$$

Writing and Predicting Chemical Formulas, Nomenclature, and Stoichiometry

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