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Question How much faster do ammonia (NH3) molecules effuse than carbon monoxide (CO) molecules? Answer Rate of effusion is a property dependant on the molar mass of the compounds. Graham's Law sets out the method to determine the relative rates of effusion of two different compounds. Specifically that the square of the inverse of a molecules mass is proportional to its rate of effusion. rate of effusion = 1/[molecular weight]1/2 For determining the relative rate of effusion vs a different compound (or element) the same setup is employed: rate of effusion(a)/rate of effusion(b) = [molecular weight(b)]1/2/[molecular weight(a)]1/2 Now, armed with the molecular weight of ammonia (17.03 g/mol) and the molecular weight of carbon monoxide (28.01 g/mol) we can determine how much faster ammonia effuses than carbon monoxide. rate of effusion(NH3)/rate of effusion(CO) = [28.01(CO)]1/2/[17.03(NH3)]1/2 rate of effusion(NH3)/rate of effusion(CO) = 5.29/4.13 = 1.28 So, ammonia diffuses approximately 1.28 times faster than carbon monoxide. |
