Moles - Percent Composition

Moles - Percent Composition

Multiple Choice

What is the percent by mass of fluorine in CaF₂ (gram-formula mass = 78 g/mol)?

• 24%

• 49%

• 51%

• 65%

Multiple Choice

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

• 20%

• 27%

• 46%

• 53%

Multiple Choice

A compound is a hydrate when it...

• is composed of only hydrogen and oxygen

• is a state of water

• contains water in the compound

• repels water from the compound

Multiple Choice

How do you calculate the percent by mass of an element in a compound? 

• Add up the mass of protons and neutrons, then divide by two.

• Divide the mass of the element by the total mass of the compound and multiply by 100.

• Add up the atomic masses of the elements, then divide by the number of the elements.

• Find the relative mass of any atom by adding the number of protons to the number of neutrons, then dividing by that total number.