Mole calculations, empirical and molecular formulae

Question 1 of 10

What is the mass of 0.5 mol of potassium hydroxide, KOH?

Question 2 of 10

A compound contains 40% carbon, 6.7% hydrogen and 53.3% oxygen by mass. Its relative molecular mass is 60. (C = 12, H = 1, O = 16) (a) Find its empirical formula. (b) Find its molecular formula.

Question 3 of 10

Percentage of nitrogen in NH₄NO₃ (N = 14, H = 1, O = 16) is

Question 4 of 10

A compound contains 85.7% carbon, 14.3% hydrogen by mass. Its relative molecular mass is 56. (C = 12, H = 1, O = 16) (a) Find its empirical formula. (b) Find its molecular formula.

Question 5 of 10

One mole of oxygen molecules has a mass of 16 g.

Question 6 of 10

How many moles are in 200 g of calcium carbonate, CaCO₃?

Question 7 of 10

A compound contains 40% carbon, 6.7% hydrogen and 53.3% oxygen by mass. Its relative molecular mass is 180. (C = 12, H = 1, O = 16) (a) Find its empirical formula. (b) Find its molecular formula.

Question 8 of 10

What volume does 0.2 mol of hydrogen chloride gas occupy at s.t.p.? (molar volume = 22.4 dm³)

Question 9 of 10

How many moles are in 11.2 g of potassium hydroxide, KOH?

Question 10 of 10

How many molecules are in 2 mol of aluminium oxide? (L = 6.02 × 10²³)