Help with chemistry question! 10 its Rate of formation?

[匿名]

2019-02-20 1:31 pm

H2(g) +Br2(g)--->2HBr (g)

Calculate the avg reaction rate b/w 0-25s
-I got 0.010M/s

Calculate the instantaneous rate of formation of HBr at 50 s?

the answer is 0.012M/s but how do you get that??

更新1:

****I should add that it should be done WITHOUT using Calculus since this is a class that doesn't require it as a prerequisite*****

回答 (1)

胡雪8°

2019-02-20 2:15 pm

✔ 最佳答案

Calculate the avg reaction rate b/w 0-25s

At t = 0 s: [Br₂] = 1.0 M
At t = 25 s: [Br₂] = 0.75 M

Average rate between 0-25 s
= -Δ[Br₂]/Δt
= -(0.75 - 1.0) / (25 - 0) M/s
= 0.010 M/s

====
Calculate the instantaneous rate of formation of HBr at 50 s.

Refer to the diagram below. Draw a tangent at 50 s.

Instantaneous rate of consumption of Br₂ at 50 s)
= -(Tangent of the slope at 50 s)
= - (0.15 - 0.75) / (120 - 20) M/s
= 0.006 M/s

H₂(g) +Br₂(g) → 2HBr(g)
Mole ratio Br₂ : HBr₂ = 1 : 2

Instantaneous rate of formation of HBr at 50 s
= (Instantaneous rate of consumption of Br₂ at 50 s) × 2
= (0.006 M/s) × 2
= 0.012 M/s

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