Question

The data below apply to the formation of urea from ammonium cyanate, NH4CNO→NH2CONH2. Initially 22.9 g of ammonium cyanate was dissolved in in enough water to prepare 1.00 dm3 of solution. Determine the order of the reaction, the rate constant, and the mass of ammonium cyanate left after 300 min.
t/min
0
20.0
50.0
65.0
150
m(urea)/g
0
7.0
12.1
13.8
17.7

Answer 1

Answer:

The order of the reaction is zero. The rate constant is 0.597M-1 min-1

Explanation:

As the molecular weights of both; ammonium cyanate and urea are the same. According to the reaction, 1 mole of ammonium cyanate forms 1 mole of urea hence the mass at any time the mass of urea is equal to the mass of ammonium cyanate.

Here, first, we required the initial concentration of ammonium cyanate:   [NH4CNO]0 =$\frac{Amount of NH4CNO}{molar mass per L}$

=22.9 /60.35 g /mol / 1 l = 0.373 M

To calculate the concentration of ammonium cyanate at any uses the following expression:

[NH4CNO]t =

0.373 M- $/\frac{Amount of urea}{molar mass per L}$ =

[NH4CNO]t =           0.373M         -  $\frac{Amount of urea}{60.35}$/ g/mol/l

By using linear regression, we can confirm that the /[ initial concentration ] vs. time is linear. Then the slope of reaction:

k= slope =0. 0597 M-1Min-1.