Answer:
a) Speed of the reaction = 0.002083 mol/L.s
b) The rate of disappearance of A₂ during this period of time = 0.002083 mol/L.s
c) The rate of appearance of AB₃ = 0.004167 mol/L.s
Explanation:
English Translation
During a study of the reaction rate
A₂ (g) + 3B₂ (g) → 2 AB₃ (g),
it is observed that in a closed container containing a certain amount of A₂ and 0.75 mol / L of B₂, the concentration B₂ decreases to 0.5 mol / L in 40 seconds.
a) What is the speed of the reaction?
b) What is the rate of disappearance of A₂ during this period of time?
c) What is the rate of appearance of AB₃?
Solution
The rate of a chemical reaction is defined as the time rate at which a reactant is used up or the rate at which a product is formed.
It is the rate of change of the concentration of a reactant (rate of decrease of the concentration of the reactant) or a product (rate of increase in the concentration of the product) with time.
Mathematically, for a balanced reaction
aA → bB
Rate = -(1/a)(ΔA/Δt) = (1/b)(ΔB/Δt)
The minus sign attached to the change of the reactant's concentration indicates that the reactant's concentration decreases.
And the coefficients of each reactant and product in the balanced reaction normalize the rate of reaction for each of them
So, for our given reaction,
A₂ (g) + 3B₂ (g) → 2 AB₃ (g)
Rate = -(ΔA₂/Δt) = -(1/3)(ΔB₂/Δt) = (1/2)(ΔAB₃/Δt)
a) Speed of the reaction = Rate of the reaction
But we are given information on the change of concentration of B₂
Change in concentration of B₂ = ΔB₂ = 0.50 - 0.75 = -0.25 mol/L
Change in time = Δt = 40 - 0 = 40 s
(ΔB₂/Δt) = (-0.25/40) = -0.00625 mol/L.s
Rate of the reaction = -(1/3)(ΔB₂/Δt) = (-1/3) × (-0.00625) = 0.002083 mol/L.s
b) The rate of disappearance of A₂ during this period of time
Recall
Rate = -(ΔA₂/Δt) = -(1/3)(ΔB₂/Δt)
-(ΔA₂/Δt) = -(1/3)(ΔB₂/Δt)
Rate of disappearance of A₂ = -(ΔA₂/Δt) = -(1/3)(ΔB₂/Δt) = (-1/3) × (-0.00625) = 0.002083 mol/L.s
c) The rate of appearance of AB₃
Recall
Rate = -(1/3)(ΔB₂/Δt) = (1/2)(ΔAB₃/Δt)
(1/2)(ΔAB₃/Δt) = -(1/3)(ΔB₂/Δt)
(ΔAB₃/Δt) = -(2/3)(ΔB₂/Δt)
rate of appearance of AB₃ = (ΔAB₃/Δt) = -(2/3)(ΔB₂/Δt) = (-2/3) × (-0.00625) = 0.004167 mol/L.s
Hope this Helps!!!
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