1. How many molecules does 36.0 grams of water represent?

Change the following masses to number of particles by:

A) dividing by the molar mass to get the number of moles, and then

B) multiplying number of moles by Avogadros number

mol = grams/molar mass

To find the number of molecules in 36.0 grams of water, we can follow these steps:

Step A: Convert grams to moles.
1. Determine the molar mass of water (H2O). The molar mass of hydrogen (H) is approximately 1.01 grams/mol, and the molar mass of oxygen (O) is approximately 16.00 grams/mol.
Therefore, the molar mass of water (H2O) is (2 * 1.01 g/mol) + (1 * 16.00 g/mol) = 18.02 grams/mol.
2. Divide the mass of water (36.0 grams) by the molar mass of water (18.02 grams/mol) to get the number of moles.
36.0 g / 18.02 g/mol ≈ 1.994 moles of water.

Step B: Convert moles to molecules.
1. Multiply the number of moles by Avogadro's number, which is approximately 6.022 x 10^23 molecules/mol.
1.994 mol * (6.022 x 10^23 molecules/mol) ≈ 1.200 x 10^24 molecules of water.

Therefore, 36.0 grams of water represents approximately 1.200 x 10^24 molecules.