Aqa Gcse Chemistry Unit 1 Essay
C 1: Fundamental ideas:
C 1.1. Atoms, elements and compounds: * All substances are made up of atoms. * Elements contain only one atom. * Compounds contain more than one atom. * An atom has a tiny nucleus in its centre, surrounded by electrons.
C 1.2. Atomic structure: * Atoms are made up of protons, neutrons and electrons. * Protons and electrons have equal and opposite electrical charges. Protons are positively charged, and electrons are negatively charged. * Neutrons have no electrical charge. They are neutral. * Atomic number = number of protons (number of electrons.) * Mass number = number of protons and neutrons. * Atoms are arranged in the periodic table in order …show more content…
C 3.2. Irons and steels: * We extract iron from iron ore by reducing it using carbon in a blast furnace. * Pure iron is too soft for it to be very useful. * Carefully controlled quantities of carbon and other elements are added to iron to make alloys of steel with different properties. * Important examples of steels are: * Low carbon steels, which are easily shaped. * High carbon steels, which are very hard * Stainless steels, which are resistant to corrosion.
C 3.3. Aluminum and titanium: * Aluminum and titanium are useful because they are resistant to corrosion. * Aluminum requires the electrolysis of molten aluminum oxide to extract it as it is too reactive to reduce it using carbon. * Aluminum and titanium are expensive because extracting them from their ores involves many stages and requires large amounts of energy.
C 3.4. Extracting copper: * Most copper is extracted by smelting (roasting) copper rich ores, although our limited supplies of ores are becoming scarce. * Copper can be extracted from copper solutions using electrolysis or by displacement using scrap iron. * Scientists are developing ways to extract copper that use low-grade copper ores. Bacteria are used in bioleaching and plants in phytomining.
C 3.5. Useful metals: * The transition metals are found in the