Question

[N2H4F2], M time (s)

2.03 x 10-4     0.00

1.25 x 10-4     20.0

7.48 x 10-5     40.0

4.54 x 10-5     60.0

2.75 x 10-5     80.0

1.67 x 10-5    100.0

1.01 x 10-5    120.0

A. Graph the data and find the order with respect to [N2H4F2]

B. Calculate K

C. Write the rate equation

D. Calculate the half-life

Answer 1

(A)

Assuming first order reaction, first order integrated rate constant equation is,

k = (1/t)ln[N₂H₄F₂]₀/[N₂H₄F₂]_t

case(1)

k = (1/20)ln(2.03*10^-4/1.25*10^-4)

k = 0.02424 s^-1.

Case (2)

k = (1/40)*ln(2.03*10^-4 / 7.48 * 10^-5)

k = 0.02496 s^-1

Case (3)

k = (1/60)*ln(2.03*10^-4 / 4.54 * 10^-5)

k = 0.02496 s-1

Case(4)

k = (1/80)*ln(2.03*10^-4 / 2.75 * 10^-5)

k = 0.02499 s^-1

SO, in all the cases we are getting constant k value,

The given reaction follows first order kinetices.

(B)

k = 0.02496 s^-1 ( as calculated above)

(C)

Rate = k[N₂H₄F₂]

(D)

Half life time = 0.693 / k = 0.693 / 0.02496 = 27.76 s