# How many atoms of hydrogen are in 220 g of hydrogen peroxide (H_2 O_2)?

## Question:

How many atoms of hydrogen are in 220 g of hydrogen peroxide {eq}(H_2 O_2) {/eq}?

## Molar Mass:

Molar Mass is a bulk property of a substance that is defined as the mass of the sample chemical compound divided by the amount of substance in the sample measured in the number of moles. Molar mass is used to determine other variables pertaining to the sample including its number of atoms present in the sample.

Given:

{eq}m_{H_2 O_2} = 220 \ g {/eq} Mass of hydrogen peroxide sample

{eq}mm_{H_2 O_2} = 34.0147 \frac {g}{mol} {/eq} Molar mass of hydrogen peroxide sample

{eq}N_A = 6.022 \times 10^{23} \frac {atoms}{mol} {/eq} Avogradro's number

To solve for the number of atoms of hydrogen present in the sample, we can use dimensional analysis with the given parameters above as,

{eq}220 \ g \ H_2 O_2 * (\frac {1 \ mol \ H_2 O_2}{34.0147 \ g \ H_2 O_2}) * (\frac {2 \ mol \ H}{1 \ mol \ H_2 O_2}) * (\frac {6.022 \times 10^{23} \ atoms \ H}{1 \ mol \ H}) = \boxed {7.79 \times 10^{24} \ atoms \ H} {/eq} 