Asid Mine Drainage

3. The rate of the reaction between hemoglobin (Hb) and carbon monoxide (CO) was studied at 20˚C. The following data were collected, with all concentration units in µmol/L.

Experiment | [Hb]0 (µmol/L) | [CO]0 (µmol/L) | Initial rate (µmol L-1s-1) |

1 | 2.21 | 1.00 | 0.619 |

2 | 4.42 | 1.00 | 1.24 |

3 | 4.42 | 3.00 | 3.71 |

a) Determine the orders of this reaction with respect to Hb and CO.

b) Determine the rate law.

c) Calculate the value of the rate constant

d) What would be the initial rate for an experiment with [Hb]0 = 3.36 µmol/L and [CO]0 = 2.40 µmol/L? (12 marks)

a) Experiments 1 and 2 have the same concentration of CO but different concentrations of Hb, so we can find the order of the reaction with respect to Hb using these experiments. Upon inspection, we can see that while the concentration of Hb is doubled from 1 to 2, the rate is also doubled. This tells us that the reaction is first order with respect to Hb. We can also set up the ratio of the rate laws.

A hemoglobin concentration of 2.21mmol/L is equal to 2.21 x 10-6 mol/L.

Rate 2 = k[Hb]0x[CO]0y

Rate 1    k[Hb]0x[CO]0y

1.24  = k(4.42)x(1.00)y

0.619   k(2.21)x(1.00)y

2 = (4.42/2.21)x = (2)x

x = 1 = order of reaction with respect to Hb

Experiments 2 and 3 have the same concentration of Hb but differing concentrations of CO, the concentration of CO triples from 2 to 3,

Rate 3 = 3.71 = k(4.42)x(3.00)y

Rate 2    1.24    k(4.42)x(1.00)y

3 = (3.00/1.00)y = (3)y

y = 1 = order of reaction with respect to CO

b) The rate law, given the orders we found in a), is

Rate = k[Hb][CO]

The reaction is first order with respect to both reactants, and second order

overall.

c) Rate = k[Hb][CO]

k = Rate/[Hb][CO]

= (0.619 µmol/L·s)/(2.21 µmol/L)(1.00 µmol/L)

= 0.280 L/ µmol·s

d) Rate = k[Hb][CO]

= (0.280 L/ µmol·s)(3.36 µmol/L L)(2.40 µmol/L)

= 2.26 µmol/L·s

6. Draw the structure of each compound:

b)...