Naphthalene, C10H8, an ingredient in mothballs, has a molar mass of 128.18 g/mol. How many molecules of naphthalene are in a mothball that has 6.000 g of naphthalene?

2.83 × 10²² molecules.

Explanation:

Using the formula below to calculate the number of moles of Naphthalene:

mole = mass/molar mass

Where;

mass = 6.00g

Molar mass = 128.18 g/mol

mole = 6/128.18

mole = 0.047mol

To calculate the number of molecules of naphthalene in the mothballs, we multiply the number of moles (n) by Avagadro's number i.e.

number of molecule = n × 6.02 × 10^23

number of molecules = 0.047 × 6.02 × 10^23

= 0.283 × 10²³

= 2.83 × 10²² molecules.