Question

I have calculated 23 grams of water in a laboratory. What is the amount of molecules

present in this amount?

a. None of the above

b. 8.3x10^24 molecules

c. 6.9x10^23 molecules

d. 7.7x10^23 molecules

e. 5.6x10^25 molecules

Answer 1

d. 7.7x10^23 molecules

Step-by-step explanation:

Given the following data:

Mass of water (H2O) = 23g

To find the number of molecules;

First of all, we would determine the number of moles;

`Number \; of \; moles = \frac {mass}{molar mass}`

Molar mass of water (H2O) = (1 * 2) + 16 = 18 g/mol

Substituting into the equation, we have

`Number \; of \; moles = \frac {23}{18}`

Number of moles = 1.2778 moles

Now, to find the number of water molecules;

We know that Avogadro constant is equal to 6.02 * 10^23 mol¯¹

Number of water molecules = number of H2O moles * Avogadro constant

Substituting into the equation, we have;

Number of water molecules = 1.2778 × 6.02 * 10^23

Number of water molecules = 7.7 × 10^23 atoms.