Question

The mass of a lethal gas (HCN) is measured ot be 5.50 lbs. If this gas is incinerated in a high temperature oven with a volume of 750 cubic feet determine the temperature of the oven. Assume that the gas is at the same pressure as the atmosphere which is 755 Torr and the temperature of the gas is the same as the oven. (1 Cubic Ft = 28.3168466 Liters) (454 g= 1 lbs)

A) 2109K
B) 2778K
C) 3021K
D) 2505K

I got 2781K so my answers is off, im not sure what i did wrong

Answer 1

1 Ibs = 454 gm then 5.50 lbs = 2497 gm

molar mass of HCN = 27 gm/mol then 2497 gm = 2497/27 = 92.48148 mole

mole of HCN = 92.39456 mole

1 cubic foot = 28.3168466 liter then 750 cubic foot = 21237.63495 liter

volume of HCN = 21237.63495 liter

use ideal gas equation to calculate tempreture

Ideal gas equation

PV = nRT             where, P = atm pressure= 755 torr = 0.993421 atm

V = volume in Liter = 21237.63495 L

n = number of mole = 92.48148 mol

R = 0.08205L atm mol^-1 K^-1 =Proportionality constant = gas constant,

T = Temperature in K = ?

We can write ideal gas equation

T = PV/nR

substitute the value in above equation

T = 0.99342121237.63495/92.48148 0.08205

T = 2780.4 K

Answer - B)2778K

there is 2 to 3 K variation because values are big and more no. of value in calculation and value after decimal point considration is also reason of some amount of error.