quantity	Response
order with respect to [NO]	Table answer rNO_Response
order with respect to [H $_{2}$ ]	Table answer rH2_Response
overall order	Table answer rOverall_Response

3(b)Rate Equations Reaction MechanismsMedium2 marks

In experiment 1, the rate of the reaction is

2.80 \times 1 0^{- 10}

mol dm

^{- 3}

^{- 1}

when [NO] is

5.00 \times 1 0^{- 2}

mol dm

^{- 3}

and [H

_{2}

] is

8.00 \times 1 0^{- 2}

mol dm

^{- 3}

Calculate the value of the rate constant,

k

, in experiment 1. State the units of

k

units

3(c)(i)Rate Equations Reaction MechanismsMedium1 mark

Experiment 2 is carried out under different conditions from experiment 1. The value of

k

for experiment 2 is

2.13 \times 1 0^{- 5}

. In experiment 2, a large excess of NO is used. The initial value of [H

_{2}

] is

1.20 \times 1 0^{- 3}

mol dm

^{- 3}

A graph of [H

_{2}

] against time for experiment 2 shows that the reaction has a constant half-life. Explain why the graph shows a constant half-life, referring to:

Answer

0 words

3(c)(ii)Rate Equations Reaction MechanismsMedium2 marks

Calculate the half-life, in s, of the reaction in experiment 2 and state the time taken, in s, for the value of [H

_{2}

] to fall to

7.50 \times 1 0^{- 5}

mol dm

^{- 3}

half-life

time taken for [H

_{2}

] to fall to

7.50 \times 1 0^{- 5}

mol dm

^{- 3}

3(d)(i)Rate Equations Reaction MechanismsMedium2 marks

The overall reaction of nitrogen monoxide with hydrogen has a three-step mechanism.

2NO + 2 H_{2} \to N_{2} + 2 H_{2} O

Part of this mechanism is shown.

step 1 2NO ⇌ N_{2} O_{2}

step 2 \dots\dots\dots \to \dots\dots\dots

step 3 N_{2} O + H_{2} \to N_{2} + H_{2} O

Complete the mechanism by writing an equation for step 2.

Answer

0 words

3(d)(ii)Rate Equations Reaction MechanismsMedium1 mark

It can be deduced that step 1 is not the rate-determining step of the reaction. Explain why.

Answer

0 words