Question

In an 11.3 second time period, the decrease in the gaseous reactant A is measured from 871 torr to 419 torr. Referencing the equation : 2A(g) → 3C(g) + D(g), what is the rate of appearance of C(g) ? A 27.7 torr/sec B 40.0 torr/sec C 60.0 torr/sec D 20.0 torr/sec E 77.0 torr/sec

Answer 1

2A(g) → 3C(g) + D(g)

Rate of reaction = - rate of disappearance of A = rate of appearance of C

rate of disappearance of A = 1/2(ΔA/Δt)

ΔA = change in concentration (or pressure if reactant is gas) = 871 - 419 = 452 torr

Δt = time period in which above change in concentration accurs = 11.3 s

(ΔA/Δt) is multiplied by 1/2 because stiochiometric coefficint of A is 2.

rate of disappearance of A = 1/2( 452/11.3) = 20 torr/s

rate of appearance of C = rate of disappearance of A

1/3(ΔC/Δt) =rate of disappearance of A

(ΔC/Δt) = 3 X rate of disappearance of A = 3 X 20 = 60 torr/s