Respuesta :
The question is incomplete, here is the complete question:
A solution is made by mixing of 51 g of heptane and 127 g of acetyl bromide. Calculate the mole fraction of heptane in this solution. Round your answer to 3 significant digits.
Answer: The mole fraction of heptane in the solution is 0.330
Explanation:
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] .....(1)
- For heptane:
Given mass of heptane = 51 g
Molar mass of heptane = 100.2 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of heptane}=\frac{51g}{100.2g/mol}=0.509mol[/tex]
- For acetyl bromide:
Given mass of acetyl bromide = 127 g
Molar mass of acetyl bromide = 123 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of acetyl bromide}=\frac{127g}{123g/mol}=1.032mol[/tex]
Mole fraction of a substance is given by:
[tex]\chi_A=\frac{n_A}{n_A+n_B}[/tex]
Moles of heptane = 0.509 moles
Total moles = [0.509 + 1.032] = 1.541 moles
Putting values in above equation, we get:
[tex]\chi_{(heptane)}=\frac{0.509}{1.541}=0.330[/tex]
Hence, the mole fraction of heptane in the solution is 0.330
