Practice with Hydrates

What is the approximate percent composition by mass of CaBr₂ (formula mass = 200)?

• 20% calcium and 80% bromine

• 25% calcium and 75% bromine

• 30% calcium and 70% bromine

• 35% calcium and 65% bromine

What is the percent composition by mass of aluminum in Al₂(SO₄)₃ (gram formula mass = 342 grams/mole)?

• 7.89%

• 20.8%

• 15.8%

• 36.0%

A 4.4 gram sample of a hydrate was heated until the water of hydration was driven off. The anhydrous compound remaining had a mass of 3.3 grams. What is the percentage by mass of water in the hydrate?

• 75%

• 33%

• 67%

• 25%

A student obtained the following data to determine the percent by mass of water in a hydrate. What is the approximate percent by mass of water in the hydrated salt?

• 2.5%

• 88%

• 12%

• 98%

Calculate the molar mass (mass of 1 mole = gram formula mass) of Ba(C₂H₃O₂)₂

• 255.3 g/mol

• 237.3 g/mol

• 228.3 g/mol

• 196.3 g/mol

What is the percent composition by mass of oxygen in the compound MgSO₄ (gram formula mass = 120 g/mol)?

• 20%
• 27%
• 46%
• 53%

How many Hydrogen atoms are in the formula: 4H₂O?

• 6
• 8
• 2
• 4

Tags

NGSS.MS-PS1-1