Q: A student decomposes 34.0 g of ammonia (NH$$_3) $$and obtains 28.0 g of nitrogen and 6.0 g of hydrogen. What is the mass ratio of nitrogen to hydrogen in ammonia?

$$\frac{28.0\,\text{g N}}{6.0\,\text{g H}} = 4.7:1$$

Q: What is the formula mass of $$\text{MgCl}_2$$? (Atomic masses: Mg = 24.31 amu, Cl = 35.45 amu)

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

Q: Which of the following is a polyatomic ion found in household bleach?

hypochlorite ($$\text{ClO}^-)$$

Q: Which of the following acids contains the chlorate ion?

chloric acid ($$\text{HClO}_3)$$

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 8:1.

Question 2

A student decomposes 34.0 g of ammonia (NH$$_3) $$and obtains 28.0 g of nitrogen and 6.0 g of hydrogen. What is the mass ratio of nitrogen to hydrogen in ammonia?

Accepted Answer

$$\frac{28.0\,	ext{g N}}{6.0\,	ext{g H}} = 4.7:1$$

Question 3

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

Accepted Answer

$$	ext{Mg(NO}_3)_2$$

Question 4

How many oxygen atoms are present in one formula unit of $$	ext{Mg(NO}_3)_2$$?

Accepted Answer

6

Question 5

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

Accepted Answer

A compound has elements combined in fixed, definite proportions.

Question 6

What is the empirical formula for glucose, $$	ext{C}_6	ext{H}_{12}	ext{O}_6$$?

Accepted Answer

$$	ext{CH}_2	ext{O}$$

Question 7

Which of the following is a molecular element?

Accepted Answer

$$	ext{Cl}_2$$

Question 8

Which of the following compounds is ionic?

Accepted Answer

$$	ext{Na}_2	ext{SO}_4$$

Question 9

What is the correct name for $$	ext{FeCl}_2$$?

Accepted Answer

iron(II) chloride

Question 10

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

Accepted Answer

$$	ext{Al}_2	ext{O}_3$$

Question 11

What is the correct name for $$	ext{K}_2	ext{SO}_4$$?

Accepted Answer

potassium sulfate

Question 12

Which of the following is the correct name for $$	ext{N}_2	ext{O}_5$$?

Accepted Answer

dinitrogen pentoxide

Question 13

What is the formula mass of $$	ext{MgCl}_2$$? (Atomic masses: Mg = 24.31 amu, Cl = 35.45 amu)

Accepted Answer

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

Question 14

Which of the following is the correct name for $$	ext{H}_2	ext{SO}_4 (aq$$)?

Accepted Answer

sulfuric acid

Question 15

Which of the following is a polyatomic ion found in household bleach?

Accepted Answer

hypochlorite ($$	ext{ClO}^-)$$

Question 16

Which of the following is the correct name for $$	ext{CuSO}_4$$?

Accepted Answer

copper(II) sulfate

Question 17

What is the correct formula for ammonium nitrate?

Accepted Answer

$$	ext{NH}_4	ext{NO}_3$$

Question 18

Which of the following acids contains the chlorate ion?

Accepted Answer

chloric acid ($$	ext{HClO}_3)$$

Question 19

A compound contains 2.0 g of hydrogen and 16.0 g of oxygen. What is the empirical formula of the compound?

Accepted Answer

$$	ext{H}_2	ext{O}$$

Chapter 5: Molecules and Compounds – Structured Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards