Question

A sample of carbon dioxide (CO2) has a mass of 52.0g. How many oxygen atoms are present?

Answer 1

Answer:

7.11 x 10²³ atoms of oxygen

Explanation:

Given parameters:

Mass of Carbon dioxide  = 52g

Unknown:

Number of oxygen atoms present = ?

Solution:

To solve this problem, we need to first find the mass of oxygen in the compound.

 Molar mass of CO₂   = 12 + 2(16)  = 44g/mol

 Mass of oxygen  = $\frac{32}{44}$ x 52  = 37.8g

  Number of moles of oxygen  = $\frac{mass}{molar mass}$    = $\frac{37.8}{32}$    = 1.18moles

So;

       1 mole of a substance contains  6.02 x 10²³ atoms

1.18 mole of oxygen will contain 1.18 x 6.02 x 10²³ = 7.11 x 10²³ atoms of oxygen