Question

Sucrose (C12H22O11), which is commonly known as table sugar, reacts in dilute acid solutions to form two simpler sugars, glucose and fructose, both of which have the formula C6H12O6: At 23 ∘C and in 0.5 MHCl, the following data were obtained for the disappearance of sucrose:

Time (min)	C12H22O11(M)
0	0.316
39	0.274
80	0.238
140	0.190
210	0.146

What is the rate constant?

k =

3.68×10−3

min−1

b)Using this rate constant, calculate the concentration of sucrose at 39, 80, 140, and 210 min if the initial sucrose concentration was 0.316 M and the reaction was first order in sucrose.

Answer 1

k = 3.68 x 10^-3 min-1

Ao = 0.316 M

At = ?

1 ) at 39 min

k = 1/t * ln (Ao / At)

3.68 x 10^-3 = 1/39 ln (0.316 /At)

0.1435 = ln (0.316 /At)

At = 0.273 M

concentration = 0.273 M

2) at 80 min

k = 1/t * ln (Ao / At)

3.68 x 10^-3 = 1/80 ln (0.316 /At)

At = 0.235 M

concentration = 0.235M

3) at 140 min

k = 1/t * ln (Ao / At)

3.68 x 10^-3 = 1/140 ln (0.316 /At)

At = 0.189 M

concentration = 0.189M

4) at 210 min

k = 1/t * ln (Ao / At)

3.68 x 10^-3 = 1/210 ln (0.316 /At)

At = 0.146M

concentration = 0.146 M