Date of publication: 2017-08-30 17:34
Additional guidance: Higher Tier candidates should be able to explain the properties of graphite in terms of weak intermolecular forces between the layers.
The Teachers' Notes provide suggestions on how to incorporate ISAs into the scheme of work. About five lessons should be allowed for the ISA: one lesson for discussion, research and planning one lesson for the completion of Section 6 one or two lessons for completing the experiment and processing their results and one lesson for completing Section 7 of the ISA.
i) The electrolysis of sodium chloride solution produces hydrogen and chlorine. Sodium hydroxide solution is also produced. These are important reagents for the chemical industry, eg sodium hydroxide for the production of soap and chlorine for the production of bleach and plastics.
Hot temperatures can give rise to thermal expansion in rocks and cool temperatures can cause rocks to contract. In areas such as deserts where the temperature is hot during the day, rocks get hot and can expand by a small amount. During the night the temperature can drop significantly making it very cold and so the rocks contract. This continuous expansion of the rock during the day and contraction during the night exerts stress on the rock and cracks form eventually causing pieces of the rock to fall away.
a) Nanoscience refers to structures that are 6–655nm in size, of the order of a few hundred atoms. Nanoparticles show different properties to the same materials in bulk and have a high surface area to volume ratio, which may lead to the development of new computers, new catalysts, new coatings, highly selective sensors, stronger and lighter construction materials, and new cosmetics such as sun tan creams and deodorants.
Candidates may be provided with information for comparison and evaluation. For example, they may be given information about the ingredients of a particular food or the components of a fuel, but will not be expected to have knowledge of the constituents of commercial products beyond that specified in the subject content for this unit.
Common electrical appliances found in the home will be examined. Examples will not be limited to electrical appliances however, in this case all the information would be given in the question.
Examination questions will use examples that are both familiar and unfamiliar to candidates. All applications will use the knowledge and understanding developed through the substantive content.