Moles, Percent Composition, Empirical and Molecular Formulas

How many molecules are there in 31.8 moles of water? (H₂O has a molar mass of 18.0 g/mol)

• 572 g

• 1.91 x 10²⁵ molecules

• 5.28x 10-²⁵ molecules

• 1.77 g

How many particles are in a mole?

• 602

• 602 million

• 602 moles

• 6.02 x 10²³

Which conversion factor should be used for the following question " How many molecules are there in 4.00 moles of glucose, C₆H₁₂O₆? 

• mole = 78.12 g

• mole = 22.4 L 

• mol = 6.02x 10²³ particles 

• more than one

What is the mass of one mole of aluminum?

• 27 g

• 13 g

• 54 g

• 14 g

The mass of one mole of substance is called...

• molecular mass

• mole constant

• molar mass

• atomic weight

What is the mass of 1 mole of sulfur?

• 16g

• 32g

• 6.02x10²³g

• 1g

How many moles of uranium would 400. grams make?

• 1.68 mol

• 0.595 mol

• 95,200 mol

• 2.41 x 10²⁶

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

• 20%

• 27%

• 46%

• 53%

In which compound is the percent composition by mass of Cl equal to 42%?

• HClO (gram formula mass = 52 g/mol)

• HClO₂ (gram formula mass = 68 g/mol)

• HClO₃ (gram formula mass = 84 g/mol)

• HClO₄ (gram formula mass = 100 g/mol)

What is the percent by mass of N in (NH₄)₂S?

• 47.1%

• 68.1%

• 44.1%

• 41.1%