Question 1

Which statement best describes the law of constant composition as it applies to water?

Accepted Answer

All samples of pure water contain hydrogen and oxygen in a fixed mass ratio of $$8.0:1.$$

Question 2

A student decomposes a 36.0 g sample of water and obtains 32.0 g of oxygen. How many grams of hydrogen were produced, and does this support the law of constant composition?

Accepted Answer

4.0 g of hydrogen; yes, because the mass ratio is $$8.0:1.$$

Question 3

Which of the following is a correct chemical formula for a compound containing magnesium and nitrate ions?

Accepted Answer

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

Question 4

What is the total number of oxygen atoms in one formula unit of $$\mathrm{Mg(NO_3$)_2}$$?

Accepted Answer

6

Question 5

Which of the following best distinguishes a compound from a mixture?

Accepted Answer

A compound contains elements in fixed, definite proportions.

Question 6

Which of the following is the correct empirical formula for hydrogen peroxide, $$\mathrm{H_2O_2}$$?

Accepted Answer

$$\mathrm{HO}$$

Question 7

Which of the following compounds is classified as an ionic compound?

Accepted Answer

$$\mathrm{NaCl}$$

Question 8

What is the correct name for the compound $$\mathrm{$$FeCl_2$$}$$?

Accepted Answer

Iron(II) chloride

Question 9

Which of the following is the correct formula for aluminum oxide?

Accepted Answer

$$\mathrm{Al_2O_3}$$

Question 10

Which of the following is the correct name for $$\mathrm{$$KNO_3$$}$$?

Accepted Answer

Potassium nitrate

Question 11

Which of the following is a molecular element?

Accepted Answer

Oxygen gas, $$\mathrm{O_2$}$$

Question 12

What is the correct name for $$\mathrm{H_2SO_4} (aq$$)?

Accepted Answer

Sulfuric acid

Question 13

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

Accepted Answer

$$\mathrm{$$CaCO_3$$}$$

Question 14

What is the formula mass of $$\mathrm{NaCl}$$? (Atomic masses: Na = 22.99 u, Cl = 35.45 u)

Accepted Answer

$$58.44\ \mathrm{u}$$

Question 15

Which of the following is the correct name for $$\mathrm{N_2O_5}$$?

Accepted Answer

Dinitrogen pentoxide

Question 16

Which of the following acids is correctly paired with its formula?

Accepted Answer

Hydrochloric acid — $$\mathrm{HCl(aq)}$$

Question 17

Which of the following best describes the difference between $$\mathrm{CO}$$ and $$\mathrm{CO_2$}$$?

Accepted Answer

They are different compounds with different properties because the subscripts in their formulas are different.

Question 18

What is the correct name for $$\mathrm{Fe(NO_3$)_3}$$?

Accepted Answer

Iron(III) nitrate

Question 19

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

Accepted Answer

$$\mathrm{(NH_4$)_2SO_4}$$

Question 20

A sample of ammonia ($$\mathrm{NH_3$}) is $$decomposed and found to contain 14.0 g of nitrogen and 3.0 g of hydrogen. What is the mass ratio of nitrogen to hydrogen in ammonia?

Accepted Answer

$$4.7:1$$

Chapter 5: Molecules and Compounds – Structured Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards