Question

The rate of effusion of an unknown gas was measured and found to be 11.9 mL/min. Under identical conditions, the rate of effusion of pure oxygen (O2) gas is 14.0 mL/min. Based on this information, the identity of the unknown gas could be:

A) NO

B) CO2

C) C2H2

D) F2

please show work

Answer 1

r x = 11.9ml/min

M x   =

r O2 = 14ml/min

M O2 = 32g.mole

r x/r O2    = M O2/ M x

11.9/14    = 32/ M x

squaring on both sides

(11.9/14)^2    = ( 32/ M x)^2

0.7225        = 32/M x

M x               = 32/0.7225   = 44g/mole

molar mass of unknown gas = 44g/mole = CO2

That gas is CO2

B) CO2>>>>answer