Aflask is charged with 0.124 mol of a and allowed to react to from b according to the reaction: a(g) -> b(g). the following drata are obtained for [a] as the reaction proceeds:
time: 0.00 10.0 20.0 30.0 40.0
moles of a: 0.124 0.110 0.088 0.073 0.054
a) what is the average rate of disapperance of a between 10s and 20s?
b) what is the avergae rate of disappearance of a between 20s and 40s?
c) what is the average rate of appearance of b between 20s and 30s?
d) how many moles of b are present at 10s?
e) how many moles of b are present at 30s?

A) -0.0022mol/s

B) -0.0017mol/s

C) 1.5x10^{-3}mol/s

D) 0.014molB

E) 0.051molB

Explanation:

Hello, here the answers:

A) Consumption.

B) Consumption.

C) Production.

Since the stoichiometric coefficients are 1 for both A and B, the consumed moles of A are equal to the difference between the initial moles of A and the actual moles of A, thus:

Now, the rate of appearance:

Which positive indeed because the moles are being formed.

Another way to find is by doing it directly with the moles of A since the rates are numerically equal but differing in the sign:

D) Based on the previous analysis:

E) Again:

molB_{30s}=0.124mol-0.073mol=0.051molB

Best regards.