$24.31\ \mathrm{amu} + 2 \times 35.45\ \mathrm{amu} = 95.21\ \mathrm{amu}$

Question 1

Which statement best describes the law of constant composition?

Accepted Answer

All samples of a given compound have the same proportions of their constituent elements.

Question 2

If you decompose 36.0 g of water, how many grams of hydrogen and oxygen would you expect to obtain, based on the law of constant composition?

Accepted Answer

32.0 g O and 4.0 g H

Question 3

Which of the following is a correct chemical formula for table sugar (sucrose)?

Accepted Answer

$\mathrm{C_{12}H_{22}O_{11}}$

Question 4

What is the empirical formula for hydrogen peroxide, given its molecular formula is $\mathrm{H_2O_2}$?

Accepted Answer

$\mathrm{HO}$

Question 5

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

Accepted Answer

A compound has elements in fixed, definite proportions; a mixture has variable proportions.

Question 6

How many oxygen atoms are present in one formula unit of $\mathrm{Mg(NO_3)_2}$?

Accepted Answer

6

Question 7

Which of the following is a molecular compound?

Accepted Answer

$\mathrm{CO_2}$

Question 8

What is the correct formula for the ionic compound formed between magnesium and chlorine?

Accepted Answer

$\mathrm{MgCl_2}$

Question 9

Which of the following is the correct name for $\mathrm{FeCl_3}$?

Accepted Answer

Iron(III) chloride

Question 10

What is the formula mass of $\mathrm{MgCl_2}$? (Atomic masses: Mg = 24.31 amu, Cl = 35.45 amu)

Accepted Answer

$24.31\ \mathrm{amu} + 2 	imes 35.45\ \mathrm{amu} = 95.21\ \mathrm{amu}$

Question 11

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

Accepted Answer

Potassium nitrate

Question 12

Which of the following is a binary acid?

Accepted Answer

$\mathrm{HCl}$ (aq)

Question 13

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

Accepted Answer

Sulfuric acid

Question 14

Which of the following elements exists naturally as a diatomic molecule?

Accepted Answer

Chlorine

Question 15

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

Accepted Answer

$\mathrm{Ca(NO_3)_2}$

Question 16

Which of the following is the correct name for $\mathrm{N_2O}$?

Accepted Answer

Dinitrogen monoxide

Question 17

What is the correct name for $\mathrm{CO_2}$?

Accepted Answer

Carbon dioxide

Question 18

Which of the following statements is true about changing a subscript in a chemical formula?

Accepted Answer

It results in a completely different compound with different properties.

Question 19

Which of the following is the correct order for listing nonmetal elements in a chemical formula?

Accepted Answer

Elements to the left in the periodic table are listed before those to the right.

Chapter 5: Molecules and Compounds – Study Notes

Study Guide - Practice Questions