Question

3)The thermal decomposition of acetaldehyde is a second order reaction
CH3CHO-> CH4+CO
from the data shown below, calculate the average rate of change in the pressure of acetaldehyde between 42 and 105 s. include the correct sign and units. ( this is analogous to finding the average rate of change in concentration, just substitute pressure for concentration.)

4) for the reaction shown below which one of the following statements can you rightly assume?
2H2S (g) +O2 (g) ->2S (s)+ 2H2O (l)
a) the reaction is second order with respect to H2S and first order with respect to O2
b) the reaction is second order overall
c) the rate law is, rate= k [H2S ]2 [O2]
d) the rate law is, rate= k [H2S][O2]
e) the rate law cannot be determined from the information given

5) consider the following rate law expression: rate = k [A]2 [B]: which of the following is not true about the reaction having this expression 
a) the reaction is first order in B 
b) the reaction is overall third order
c) the reaction is second order in A
d) doubling the concentration of A doubles the rate .
e) A and B must both be reactants

6. the oxidation of NO by O3 is first order in each of the reactants, and it's rate constant is 1.5 x 10 to the 7th power M-1s-1 . if the concentration of NO and O3 are each 5.o x10 to the negative 7th power M. what is the rate of oxidation of NO in Ms-1?
a) 3.8x 10 to the negative 6th power
b) 2.5x 10 to the negative 14th power
c) 7.5 x 10 to the negative 7th power 
d) 15
e) 7.5

Answer 1

4) for the reaction shown below which one of the following statements can you rightly assume?
2H2S (g) +O2 (g) ->2S (s)+ 2H2O (l)

ans = c) the rate law is, rate= k [H2S ]² [O2]

5) consider the following rate law expression: rate = k [A]² [B]: which of the following is not true about the reaction having this expression

Ans= d) doubling the concentration of A doubles the rate .

rate = k [A]² [B]

doubling the concentration of A , gives

rate = k [2A]² [B] = 4 .  k [A]² [B] = rate increases by 4 times.

Therefore, d is not true.

6) NO + O3 ------------.> product k= 1.5 x 10⁷ M-1s-1

[NO] = [O3] = 5 x 10^-7 M

rate oxidation of NO = k [ NO] [O3]

= ( 1.5 x 10⁷ M-1s-1) (5 x 10^-7 M) (5 x 10^-7 M)

= 3.8 x10^-6 M

Therefore,

ans = a