# Help Zone

### Student Question

Secondary V • 2yr.

How do I answer this question: how many moles of oxygen are there in 2.25 g of CO2? Thank you!

Chemistry

{t c="richEditor.description.title"} {t c="richEditor.description.paragraphMenu"} {t c="richEditor.description.inlineMenu"} {t c="richEditor.description.embed"}

## Explanations (1)

• Explanation from Alloprof

Explanation from Alloprof

This Explanation was submitted by a member of the Alloprof team.

Options
Team Alloprof • 2yr.

Thank you for your question!

First, remember that a mole contains:

$$6,023•10^{23}\:particles$$

To solve the problem, you must first convert 2.25 g of CO2 in moles. The molar mass of CO2 is 44.095 g.

$$n=\frac{m}{M}$$

$$n_{CO_2}=\frac{2,25}{44,095}$$

$$n_{CO_2}≈0,0511\:moles$$

Legend:

• n: number of moles

• m: mass of the substance

• M: molar mass of the substance

Subsequently, it must be considered that in one mole of CO2 there are two moles of O. Thus:

$$n_{O}=2•n_{CO_2}=2•0,0511\:moles≈0,102\:moles$$

Don't hesitate if you have other questions!