Question

The reaction 2NO(g)+ 2H2(g) ---> N2(g)+ 2H2O(g)

was studied at 904 °C, and the data in the table were collected.

Reaction Concentration (mol/L)		Rate of Appearance of N2
[NO]	[H2]	(mol/L·s)
0.498	0.122	0.191
0.249	0.122	0.0478
0.249	0.244	0.0956
0.125	0.488	0.0482

A) Determine the order of the reaction for each reactant. reaction order in [NO] = ____ reaction order in [H2] = ____

B) Write the rate equation for the reaction. (Use k for the rate constant.) Rate = ____

C) What is the rate constant for the reaction? Rate constant = _____ L2/mol2·s

D) Find the rate of appearance of  at the instant when  = 0.330 mol/L and  = 0.325 mol/L. Rate = _____ mol/L·s

Answer 1

A)

see experiment 2 and 1:

[NO] doubles

[H2] is constant

rate becomes 4 times

so, order of NO is 2

see experiment 2 and 3:

[NO] is constant

[H2] doubles

rate doubles

so, order of H2 is 1

B)

Rate law is:

rate = k*[NO]^2*[H2]

C)

Put values from 1st row of table in rate law

rate = k*[NO]^2*[H2]

0.191 = k*0.498^2*0.122^1

k = 6.313 M-2.s-1

k = 6.313 L2/mol2.s

Answer: 6.313 L2/mol2.s

D)

rate = k*[NO]^2*[H2]

rate =6.313*0.330^2*0.325^1

rate = 0.223 M/s

rate = 0.223 mol/L.s

Answer: 0.223 mol/L.s