DP Chemistry Questionbank

Suggest two reasons why atoms are no longer regarded as the indivisible units of matter.

Suggest two reasons why atoms are no longer regarded as the indivisible units of matter.

Suggest why many chemicals, including hydrogen peroxide, are kept in brown bottles instead of clear colourless bottles.

Suggest the basis of these predictions.

Suggest one application for carbon nanotubes.

Outline one benefit of the use of these products.

Hydroelectric power plants produced 16% of the world’s energy in 2015, down from 21% in 1971.

Suggest why hydroelectric power production has a higher efficiency than the other sources given in (b) and why its relative use has decreased despite the high efficiency.

Reason for higher efficiency:

Reason for decreased use:

Magnetic resonance imaging (MRI) is an application of NMR technology using radiowaves.

Suggest why MRI is much less dangerous than imaging techniques such as X-rays and radiotracers. Use section 3 of the data booklet.

Outline one advantage of allowing all countries access to the technology to generate electricity by nuclear fission.

Suggest why the addition of plasticizers is controversial.

Oil spills can be treated with an enzyme mixture to speed up decomposition.

Outline one factor to be considered when assessing the greenness of an enzyme mixture.

What is the major reason why the pH of unpolluted rain is less than 7?

A. methane

B. carbon dioxide

C. nitrogen oxides

D. sulfur dioxide

Suggest why many chemicals, including hydrogen peroxide, are kept in brown bottles instead of clear colourless bottles.

Before its isolation, scientists predicted the existence of rhenium and some of its properties.

Suggest the basis of these predictions.

The formula q = mcΔT was used to calculate the energy released. The values used in the calculation were m = 25.00 g, c = 4.18 J g⁻¹ K⁻¹.

State an assumption made when using these values for m and c.

Hydroelectric power plants produced 16 % of the world’s energy in 2015, down from 21 % in 1971.

Suggest why hydroelectric power production has a higher efficiency than the other sources given in (b) and why its relative use has decreased despite the high efficiency.

Reason for higher efficiency:

Reason for decreased use:

Suggest one application for carbon nanotubes.

Anti-HIV drugs, such as zidovudine, often become less effective over time.

Explain the development of resistant virus strains in the presence of antiviral drugs.

The addition of partially hydrogenated cocoa butter to chocolate increases its melting point and the content of trans-fatty acids (trans-fats).

Outline two effects of trans-fatty acids on health.

Suggest why the addition of plasticizers is controversial.

Oil spills can be treated with an enzyme mixture to speed up decomposition.

Outline one factor to be considered when assessing the greenness of an enzyme mixture.

Outline one advantage of allowing all countries access to the technology to generate electricity by nuclear fission.

What is the major reason why the pH of unpolluted rain is less than 7?

A. methane

B. carbon dioxide

C. nitrogen oxides

D. sulfur dioxide

Copper(II) chloride is used as a catalyst in the production of chlorine from hydrogen chloride.

4HCl (g) + O₂ (g) → 2Cl₂ (g) + 2H₂O (g)

Calculate the standard enthalpy change, ΔH^θ, in kJ, for this reaction, using section 12 of the data booklet.

Discuss the data.

Write half-equations for the electrolysis of molten alumina using graphite electrodes, deducing the state symbols of the products.

Anode (positive electrode):

Cathode (negative electrode):

Copper(II) chloride is used as a catalyst in the production of chlorine from hydrogen chloride.

4HCl (g) + O₂ (g) → 2Cl₂ (g) + 2H₂O (g)

Calculate the standard enthalpy change, ΔH^θ, in kJ, for this reaction, using section 12 of the data booklet.

Discuss the data.