Question

A)A + 3B → 2C

[A] / M	Time / s
0.75	0
0.50	15
0.10	30

What is the average rate of the reaction with respect to A over the first 15 seconds of the reaction in M/s? (Express your answer as a decimal, not scientific notation and be mindful of significant figures)

B)At a certain time in a reaction, substance A is disappearing at a rate of 4.0 x 10⁻² M/s, substance B is appearing at a rate of  2.0 x 10⁻² Μ/s, and substance C is appearing at a rate of 6.0 x 10⁻² Μ/s.

Select the correct stoichiometry of the reaction being studied.

		2A + B → 3 C
		4A  → 2B + 3C
		2A  → B + 3C
		A + 2B  → 3C
		A  → 2B + 3C

Answer 1

A)

Given a reaction:

aA+bB→cC+dDa

rate of reaction = −1/a x Δ[A]/Δt

since 1/a = 1

rate = -Δ[A]/Δt

rate = - (0.75 - 0.5)/15 - 0

rate = - 0.25/15 = 0.0167 M/s

So average rate of the reaction = 0.0167 M/s

B)

A is disappearing at a rate of 4.0 x 10⁻² M/s, substance B is appearing at a rate of  2.0 x 10⁻² Μ/s, and substance C is appearing at a rate of 6.0 x 10^-2M/s.

So only A is disappearing and B and C are appearing Now C is appearing 3 times as faste as B and A is disappearing twice as fast as B so the correct molar stoiciometry is 2:1:3 between A disappearing B appearing abd C appearing

So the correct equation should be

2A  → B + 3C