In: Chemistry
the vapor pressure of pure carbon disulfide and carbon tetrachloride are 360. and 99.8 torr, respectively, at 298K. What is the (total vapor pressure of a solution containing 50.0g of each compound A. 460. torr B. 274 torr C 260. torr D. 33.0 torr E. 241 torr
Answer- Given, vapor pressure of CS2 = 360 torr, for CCl4 = 99.8 torr
Mass of CS2 = 50.0 g and mass of CCl4 = 50.0 g
Now we need to calculate the moles of each
Moles of CS2 = 50.0 g / 76.143 g.mol-1 = 0.657 moles
Moles of CCl4 = 50.0 g / 153.82 g.mol-1 = 0.325 moles
Total moles = 0.657 +0.325 = 0.982 moles
So mole fraction of CS2 = 0.657 moles / 0.982 mole = 0.669
Mole fraction of CCl4 = 0.325 moles / 0.982 moles = 0.331
So the partial pressure of CS2 = mole fraction * vapor pressure
= 0.669 * 360 torr
= 240.8 torr
Partial pressure of CCl4 = 0.331* 99.8 torr
= 33.04 torr
So,total pressure = 240.8 +33.04 = 273.8 torr
= 274 torr
So, is the total vapor pressure of a solution containing 50.0g of each compound is B. 274 torr