What is the mass of 24 * 10 ^ 23 water molecules?

Data: N is the number of water molecules (N = 24 * 10 ^ 23 molecules).

Const: Na – Avogadro’s number (Na = 6.022 * 10 ^ 23 mol-1); МН2О – molar mass of water (МН2О ≈ 0.018 kg / mol).

To find out the mass of a given number of water molecules, consider the equality: N / Na = mх / МН2О, from where we express: mх = МН2О * Nx / Na.

Let’s perform the calculation: mx = MH2O * N / Na = 0.018 * 24 * 10 ^ 23 / (6.022 * 10 ^ 23) ≈ 7.17 * 10 ^ -3 kg.

Answer: The mass of a given number of water molecules, according to the calculation, is 7.17 g.