In 1 hour, 18 grams of water evaporated. Determine how many molecules evaporated in 1 second.

1) Let’s translate first 1 hour into seconds.

1 hour = 60 minutes = 60 * 60 seconds = 3600 seconds.

2) It is known that the molar mass of water is 18 g / mol.

3) Let’s determine how many molecules have deteriorated in 1 second, if 18 grams of water have evaporated in 1 hour.

We apply the following formula: m / M * Na / t.

Substitute the known values into the formula and calculate the number of molecules that have evaporated in 1 second.

m / M * Na / 3600 = 18 grams / 18 g / mol * 6 * 10 ^ 23 mol / 1 h = 18 grams / 18 g / mol * 6 * 10 ^ 23 mol / 3600 = 18/18 * 6 * 10 ^ 23/3600 = 6 * 10 ^ 23 / (36 * 10 ^ 2) = 6/36 * 10 ^ 21 = 1/6 * 10 ^ 21 = 0.17 * 10 ^ 21 molecules.

Answer: 0.17 * 10 ^ 21 molecules.