At 40 C the vapor pressure of n-pentane (n-C5H12) is 873 mmand the vapor pressure of n-heptane (n-C7H16) is 92 mm. UseRaoult's Law to calculate the vapor pressure at 40 C of a 3:1 molarmixture of n-pentane and n-heptane. Do the same for a mixture of 50g of each component. At 40 C the vapor pressure of n-pentane (n-C5H12) is 873 mmand the vapor pressure of n-heptane (n-C7H16) is 92 mm. UseRaoult's Law to calculate the vapor pressure at 40 C of a 3:1 molarmixture of n-pentane and n-heptane. Do the same for a mixture of 50g of each component.
Explanation / Answer
n-pentane and n-heptane form the ideal mixture . The molarratio of the two liquids is 3 : 1 mole fractionof n-pentane is = XA= 3 /4 = 0.75 mole fractionof n-heptane is = XB = 1/4 = 0.25 PA = PoA *XA = 873 mm Hg * 0.75 = 654.75 mm Hg PB = PoB*XB = 92 mm Hg * 0.25 = 23 mmHg The pressure of the mixture P =PA + PB = 677.75 mm Hg If 50 gof each of the components is mixed then calculate the number ofmoles of each component and then calculate mole fractions.Substitute in the above equations. = 873 mm Hg * 0.75 = 654.75 mm Hg PB = PoB*XB = 92 mm Hg * 0.25 = 23 mmHg The pressure of the mixture P =PA + PB = 677.75 mm Hg If 50 gof each of the components is mixed then calculate the number ofmoles of each component and then calculate mole fractions.Substitute in the above equations.