A-Level AQA Chemistry The Mole, Avogadro & The Ideal Gas Equation: What is the mole fraction of 1.0

What is the mole fraction of 1.0 g of a compound of relative molecular mass 100.0 dissolved in 30.0 g of solvent of relative molecular mass 50.0? - AQA - A-Level Chemistry - Question 9 - 2021 - Paper 3

Question 9

$What-is-the-mole-fraction-of-1.0-g-of-a-compound-of-relative-molecular-mass-100.0-dissolved-in-30.0-g-of-solvent-of-relative-molecular-mass-50.0?-AQA-A-Level Chemistry-Question 9-2021-Paper 3.png$

What is the mole fraction of 1.0 g of a compound of relative molecular mass 100.0 dissolved in 30.0 g of solvent of relative molecular mass 50.0?

Worked Solution & Example Answer:What is the mole fraction of 1.0 g of a compound of relative molecular mass 100.0 dissolved in 30.0 g of solvent of relative molecular mass 50.0? - AQA - A-Level Chemistry - Question 9 - 2021 - Paper 3

Step 1

Calculate the moles of the compound

96%

114 rated

Answer

To find the moles of the compound, we use the formula:

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

where:

$m$ is the mass of the compound (1.0 g)
$M$ is the molecular mass of the compound (100.0 g/mol)

Thus,

$n_{compound} = \frac{1.0 \text{ g}}{100.0 \text{ g/mol}} = 0.01 \text{ mol}$

Step 2

Calculate the moles of the solvent

99%

104 rated

Answer

Similarly, for the solvent:

$n_{solvent} = \frac{m}{M}$

where:

$m$ is the mass of the solvent (30.0 g)
$M$ is the molecular mass of the solvent (50.0 g/mol)

Thus,

$n_{solvent} = \frac{30.0 \text{ g}}{50.0 \text{ g/mol}} = 0.6 \text{ mol}$

Step 3

Calculate the mole fraction of the compound

96%

101 rated

Answer

The mole fraction ( $X$ ) of the compound is calculated using the formula:

$X_{compound} = \frac{n_{compound}}{n_{compound} + n_{solvent}}$

Substituting the values:

$X_{compound} = \frac{0.01 \text{ mol}}{0.01 \text{ mol} + 0.6 \text{ mol}} = \frac{0.01}{0.61} \approx 0.016393$

So, the mole fraction is approximately $1.6 \times 10^{-2}$ .

Step 4

Final Answer

98%

120 rated

Answer

The mole fraction of the compound is approximately $1.6 \times 10^{-2}$ , which corresponds to option B.

What is the mole fraction of 1.0 g of a compound of relative molecular mass 100.0 dissolved in 30.0 g of solvent of relative molecular mass 50.0? - AQA - A-Level Chemistry - Question 9 - 2021 - Paper 3

Worked Solution & Example Answer:What is the mole fraction of 1.0 g of a compound of relative molecular mass 100.0 dissolved in 30.0 g of solvent of relative molecular mass 50.0? - AQA - A-Level Chemistry - Question 9 - 2021 - Paper 3

Calculate the moles of the compound

Calculate the moles of the solvent

Calculate the mole fraction of the compound

Final Answer

Join the A-Level students using SimpleStudy...

Other A-Level Chemistry topics to explore