Question

What is the mole fraction of potassium dichromate, K2Cr2O7, in a solution prepared from 24.42 g of potassium dichromate and 240. g of water? Report your answer in scientific notation with three significant figures

Answer 1

`6.19* 10^(-3)` is the mole fraction of potassium dichromate.

Step-by-step explanation:

Mass of potassium dichromate = 24.42 g

Moles of potassium dichromate =
`n_1=(24.42 g)/(294.185 g/mol)=0.0830 mol`

Mass of water = 240.0 g

Moles of water =
`n_2=(240.0 g)/(18.015 g/mol)=13.3222 mol`

Mole fraction is calculated by:

`\chi_1=(n_1)/(n_1+n_2)`

`\chi_1=(0.0830 mol)/(0.0830 mol+13.3222 mol)=0.00619=6.19* 10^(-3)`

`6.19* 10^(-3)` is the mole fraction of potassium dichromate.