Investigation 5: Chemical Quantities

Milk of magnesia can be used to relieve indigestion and heartburn. The active ingredient in this substance is magnesium hydroxide (Mg(OH)₂). What is the percent composition of magnesium hydroxide in this substance?

• 20.0% Mg, 40.0% O, 40.0% H

• 43.1% Mg, 51.3% O, 5.6% H

• 41.7% Mg, 54.9% O, 3.4% H

• 47.1% Mg, 48.3% O, 4.1% H

Sulfur dioxide is a compound used to preserve grapes. What volume would a 23.8 g sample of sulfur dioxide take up if it were stored at STP?

• 8.32 L

• 0.120 L

• 634 L

• 1.26 L

How many atoms are found in a 15.5 g sample of bismuth?

• 9.33 x 10²⁴ atoms

• 3.24 x 10³ atoms

• 1.26 x 10²² atoms

• 4.46 x 10²² atoms

A chemistry teacher provides students with the amount of potassium hydroxide they need in solution form. The teacher makes the solution by dissolving 42.1 g KOH into 3.0 L of solution.

What is the molarity of this solution?

• 1.3 M

• 0.75 M

• 0.25 M

• 0.44 M

Tags

NGSS.HS-PS1-5

Aluminum oxide (Al₂O₃) is extracted from bauxite and provides the major source of aluminum in the world. What mass of pure aluminum can be extracted from 655 g aluminum oxide?

• 262 g

• 309 g

• 346 g

• 368 g

Tags

NGSS.HS-PS1-7

Which of the following has the greatest mass for one mole of the compound?

• SiH₄

• CO

• CH₃OH

• C₂H₆

Sulfuric acid is purchased full-strength at 18.0 M. How many milliliters of full-strength acid are needed to prepare 500.0 mL of aqueous 0.35 M H₂SO₄?

• 13.4 mL

• 82.6 mL

• 9.70 mL

• 79.0 mL