Water H2O m = 0.20 kg is poured into the glass. Determine the amount of substance and the number

Water H2O m = 0.20 kg is poured into the glass. Determine the amount of substance and the number of water molecules in the glass.

Task data: m (mass of water poured into a glass) = 0.2 kg.

Reference values: M (molar mass of water) = 18 g / mol (0.018 kg / mol); Na (Avogadro’s number) = 6.02 * 10 ^ 23 mol-1.

1) Determine the amount of water substance in a glass: ν = m / M = 0.2 / 0.018 = 11.11 mol.

2) Determine the number of molecules in a glass: ν = N / Na, whence N = ν * Na = 11.11 * 6.02 * 10 ^ 23 = 66.9 * 10 ^ 23 molecules.

Answer: There are 11.11 mol of water in a glass, which is 66.9 * 10 ^ 23 molecules.