A) Find the gas speed of ammonia at 25.0 degrees Celsius. b) What is the rate of effusion of ammonia compared to silicon tetra bromide gas as the same temperature?

a. 661.23 m/s

b.  the rate of effusion of Ammonia = 4.5 faster than Silicon tetra bromide

Given

T = 25 + 273 = 298 K

Required

a. the gas speed

b. The rate of effusion comparison

Solution

a.

Average velocities of gases can be expressed as root-mean-square averages. (V rms)  

R = gas constant, T = temperature, Mm = molar mass of the gas particles  

From the question  

R = 8,314 J / mol K  

T = temperature  

Mm = molar mass, kg / mol  

Molar mass of Ammonia = 17 g/mol = 0.017 kg/mol

b. the effusion rates of two gases = the square root of the inverse of their molar masses:  

M₁ = molar mass Ammonia NH₃= 17

M₂ =  molar mass Silicon tetra bromide SiBr₄= 348

the rate of effusion of Ammonia = 4.5 faster than Silicon tetra bromide