Question

Match the grams of each element or compound to the corresponding number of moles of that element or compound.

Answer 1

Answer is: 20.0g H - 20.0 moles; 0.50 g Na - 0.022 moles; 2.0 x 102 mg H2O - 0.011 moles.

1) m(H) = 20.0 g; mass of hydrogen.

n(H) = m(H) ÷ M(H).

n(H) = 20 g ÷ 1 g/mol.

n(H) = 20.0 mol; amount of hydrogen.

2) m(Na) = 0.50 g; mass of sodium.

n(Na) = m(Na) ÷ M(Na).

n(Na) = 0.5 g ÷ 22.98 g/mol.

n(Na) = 0.022 mol; amount of sodium.

3) m(H₂O) = 200 mg ÷ 1000 mg/g.

m(H₂O) = 0.20 g; mass of water.

n(H₂O) = m(H₂O) ÷ M(H₂O).

n(H₂O) = 0.2 g ÷ 18 g/mol.

n(H₂O) = 0.011 mol; amount of water.

Answer 2

20.0g H = 20.0 moles
0.05 g Na = 0.022 moles
H2O = 0.011 moles