The graph shows the change in oxygen partial pressure in blood, measured at different pH values.

Explain the effect of changing pH on the percentage saturation of hemoglobin at a given partial pressure of oxygen.

Explain the biomagnification of the pesticide DDT.

Vitamins are organic compounds essential in small amounts.

State the name of one functional group common to all three vitamins shown in section 35of the data booklet.

Below are the IR spectra of two plastics (A and B); one is PETE, the other is lowdensity polyethene (LDPE).

Deduce, giving your reasons, the identity and resin identification code (RIC) of A and Busing sections 26 and 30 of the data booklet.

Describe the difference in their structures.

Explain why the difference in their structures affects their melting points.

Predict the electron domain and molecular geometries around the oxygen atom of molecule A using VSEPR

State the type of hybridization shown by the central carbon atom in molecule B.

State the number of sigma (σ) and pi (π) bonds around the central carbon atom in molecule B.

The IR spectrum of one of the compounds is shown:

COBLENTZ SOCIETY. Collection © 2018 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.

Deduce, giving a reason, the compound producing this spectrum.

Compound A and B are isomers. Draw two other structural isomers with the formula C3H6O.

The equilibrium constant, Kc, for the conversion of A to B is 1.0×108 in water at 298 K.

Deduce, giving a reason, which compound, A or B, is present in greater concentration when equilibrium is reached.

f(i).

Calculate the standard Gibbs free energy change, ∆G⦵, in kJ mol–1, for the reaction (A to B) at 298 K. Use sections 1 and 2 of the data booklet.

f(ii).

Propanone can be synthesized in two steps from propene.Suggest the synthetic route including all the necessary reactants and steps.

g(i).

Propanone can be synthesized in two steps from propene.

Suggest why propanal is a minor product obtained from the synthetic route in (g)(i).

g(ii).

Suggest why a high-octane number fuel is preferable.

Reforming reactions are used to increase the octane number of a hydrocarbon fuel.

Suggest the structural formulas of two possible products of the reforming reaction of heptane, C7H16.

b(i).

The 1H NMR spectrum of one of the products has four signals. The integration trace shows a ratio of the areas under the signals of 9 : 3 : 2 : 2.

Deduce the structural formula of the product.

b(ii).

Calculate the enthalpy change, in kJ, for the spray reaction, using the data below.

C 6 H 4 (OH) 2 (aq) → C 6 H 4 O 2 (aq) + H 2 (g) Δ H θ = + 177.0 kJ 2 H 2 O(l) + O 2 (g) → 2 H 2 O 2 (aq) Δ H θ = + 189.2 kJ H 2 O(l) → H 2 (g) + 1 2 O 2 (g) Δ H θ = + 285.5 kJ

The energy released by the reaction of one mole of hydrogen peroxide withhydroquinone is used to heat 850 cm3 of water initially at 21.8°C. Determine thehighest temperature reached by the water.

Specific heat capacity of water = 4.18 kJ kg−1 K−1.

(If you did not obtain an answer to part (i), use a value of 200.0 kJ for the energyreleased, although this is not the correct answer.)

Identify the species responsible for the peak at m/z = 110 in the mass spectrumof hydroquinone.

Identify the highest m/z value in the mass spectrum of quinone.

Determine the empirical formula of the compound using section 6 of the data booklet.

Determine the molecular formula of this compound if its molar mass is 88.12 g mol−1. If you did not obtain an answer in (a) use CS, but this is not the correct answer.

Identify each compound from the spectra given, use absorptions from the range of 1700 cm−1 to 3500 cm−1. Explain the reason for your choice, referring to section 26 of the data booklet.

Predict the number of 1H NMR signals, and splitting pattern of the –CH3 seen for propanone (CH3COCH3) and propanal (CH3CH2CHO).

Predict the fragment that is responsible for a m/z of 31 in the mass spectrum of propan‑1‑ol. Use section 28 of the data booklet.