$$3.49 \times 10$$^{24}$$ atoms

Question 1

How many of each type of atom are present in the formula $$\mathrm{(NH_4$)_2HPO_4}$$?

Accepted Answer

N: 2, H: 9, P: 1, O: 4

Question 2

What is the correct formula for a compound that has ten oxygen atoms and four phosphorus atoms?

Accepted Answer

$$\mathrm{P_4O_{10}}$$

Question 3

Which of the following is the correct formula for an ionic compound made of aluminum and oxygen?

Accepted Answer

$$\mathrm{Al_2O_3}$$

Question 4

What is the correct name for the formula $$\mathrm{$$CaCO_3$$}$$?

Accepted Answer

Calcium carbonate

Question 5

Which of the following pairs of names and formulas does NOT match?

Accepted Answer

Copper(I) nitrate: CuNO$$_3$$

Question 6

What is the name of the molecular compound $$\mathrm{SO_3$}$$?

Accepted Answer

Sulfur trioxide

Question 7

What is the correct formula for the molecular compound heptaphosphorus octafluoride?

Accepted Answer

$$\mathrm{P_7F_8}$$

Question 8

What is the oxygen-to-hydrogen mass ratio for $$\mathrm{H_2O_2}$$?

Accepted Answer

8:1

Question 9

Which of the following is a molecular compound?

Accepted Answer

Nitrogen monoxide

Question 10

Calculate the formula mass for potassium nitrate ($$\mathrm{$$KNO_3$$}). $$Use atomic masses: K = 39.10, N = 14.01, O = 16.00.

Accepted Answer

101.11 g/mol

Question 11

How many mercury atoms are in 5.8 mol of mercury?

Accepted Answer

$$3.49 	imes 10$$^{24}$$ atoms

Question 12

A 0.45 g sample of children's aspirin is decomposed to 0.27 g of carbon. What is the mass percent of carbon in the aspirin?

Accepted Answer

60.0%

Question 13

A compound has N and O. On decomposition, it produces 1.78 g of N and 4.05 g of O. What is the empirical formula?

Accepted Answer

$$\mathrm{NO_2$}$$

Question 14

Which of the following is evidence of a chemical reaction?

Accepted Answer

All of the above: color change, solid formation, gas formation, emission of light

Question 15

Which ion would NOT be a spectator ion in the precipitation reaction: $$\mathrm{Pb(NO_3$)_2(aq) + 2KCl(aq) \rightarrow $$PbCl_2$$(s) + 2KNO_3(aq)}$$?

Accepted Answer

$$\mathrm{Pb$$^{2+}$$}$$

Question 16

What type of reaction is represented by the generic equation $$\mathrm{AB + CD \rightarrow AD + CB}$$?

Accepted Answer

Double displacement reaction

Question 17

Which of the following reactions is a double displacement reaction?

Accepted Answer

$$\mathrm{KCl(aq) + $$AgNO_3$$(aq) \rightarrow AgCl(s) + $$KNO_3$$(aq)}$$

Question 18

What are the coefficients for the balanced equation: $$\mathrm{Na_3PO_4 + Ba(NO_3$)_2 \rightarrow $$NaNO_3$$ + Ba_3$(PO_4$)_2}$$?

Accepted Answer

2, 3, 6, 1

Question 19

Which of the following compounds is soluble in water and will dissociate into ions?

Accepted Answer

$$\mathrm{Na_2SO_4}$$

Introduction to Chemistry: Study Guide for Chapters 5–7 (Atoms, Compounds, Chemical Reactions, and Stoichiometry)

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