On Minggu, 11 November 2012
pheromones are compounds released by female insects to attract male insects. one pheromone compound contains 80.78% C, 13:56% H, and 5.66% O. a solution containing 1.00 grams of pheromone in 8:50 g of benzene freezes at 3:37 degrees celcius. how the molecular formula and molar mass compounds TSB? (normal freezing point of pure benzene is 5:50 degrees Celsius
Answer:
To - T = (w / Mr) (1000 / P) Kf
5.5 - 3:37 = (1/Mr) (1000/8.5) (5.1)
Mr = 282
atom C:
p Ar C / Mr pheromones = 80.78%
12 p / 282 = 80.78%
p = 19
H atom:
q Ar H / Mr pheromones = 13:56%
q / 282 = 13:56%
q = 38
O atom:
Ar r O / Mr pheromones = 5.66%
16 r / 282 = 5.66%
r = 1
check out:
Mr C19H38O = 19 * 12 + 38 + 16
Mr C19H38O = 282
