Chemistry C1

C1 1.1: Atoms, Elements and CompoundsKey Points All substances are made up of atoms Elements contain only one type of atom Compounds contain more than one type of atom An atom has tiny nucleus in its centre, surrounded by electrons.

C1 1.2: Atomic StructureKey Points Atoms are made of protons, neutrons and electrons Protons and electrons have equal and opposite electric charges. Protons are positively charged, and electrons are negatively charged Neurons have no electric chare. They are neutral Atomic number = number of protons (=number of electrons) Mass Number = number of protons + neutrons Atoms are arranged in the periodic table in order of their atomic number.

C1 1.3: The Arrangement of Electrons in AtomsKey Points The electrons in an atom are arranged in energy levels or shells Atoms with the same number of electrons in their outermost shell belong in the same group of the periodic table. The number of electrons in the outermost shell of an element's atoms determines the way that element reacts. The atoms of the unreactive noble gases (in Group 0) all have very stable arrangements of electrons.

C1 1.4: Forming BondsKey Points When atoms from different elements react together they make compounds. The formula of a compound shows the number and type of atoms that have bonded together to make that compound. When metals react with non-metals, charged particles called ions are formed. Metal atoms form positively charged ions. Non-metal atoms form negatively charged ions. These oppositely charged ions attract each other in ionic bonding. Atoms of non-metals bond to each other by sharing electrons. This is called covalent bonding.

C1 1.5: Chemical EquationsKey Points As no new atoms are ever created or destroyed in a chemical reaction: The total mass of reactants = the total mass of products. There is the same number of each type of atom on each side of balanced symbol equation.

C1 2.1: Limestone and its UsesKey Points Limestone is made mainly of calcium carbonate Limestone is widely used in the building industry The calcium carbonate in limestone breaks down when we heat it strongly to make calcium oxide and carbon dioxide. The reaction is called thermal decomposition.

C1 2.2: Reactions of CarbonatesKey Points Carbonates react with dilute acid to form salt, water an carbon dioxide Limewater turns cloudy in the test for carbon dioxide gas. A precipitate of insoluble calcium carbonate causes the cloudiness Metal carbonates decompose on heating to form the metal oxide and carbon dioxide.

C1 2.3: The 'Limestone Reaction Cycle'Key Points When water is added to calcium oxide it produces calcium hydroxide Calcium hydroxide is alkaline so it can be used to neutralise acids The reactions of limestone and its products hat you need are shown in the 'limestone reaction cycle'.

C1 2.4: Cement and ConcreteKey Points cement is made by heating limestone with clay in a kiln Mortar is made by mixing cement and sand with water Concrete is made by mixing rocks or small stones called aggregate with water.

C1 2.5: Limestone IssuesKey Points There are good and bad points about quarrying for limestone. For example, more jobs will be created but there will be a large scar on the landscape Limestone, cement and concrete all have useful properties for use as building materials but the mining and processing of limestone and its products has a major effect on our environment.

C1 3.1: Extracting MetalsKey Points A metal ore contains enough of the metal to make it economic to extract the metal. Ores are mined and might need to be concentrated before the metal is extracted and purified. We can find gold and other unreactive metals in their native state The reactivity series helps us decide the best way to extract a metal from its ore. The oxides of metals below carbon in the series can be reduced by carbon to give the metal element Metals more reactive than carbon cannot be extracted from their ores using carbon. 

C1 3.2: Iron and SteelsKey Points 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. 

C1 3.3: Aluminium and TitaniumKey Point Aluminium and titanium are useful because they resist corrosion Aluminium requires the electrolysis of molten aluminium oxide to extract it as it is too reactive to reduce using carbon Aluminium and titanium are expensive because extracting them from their ores involves many stages and requires large amounts of energy.

C1 3.4: Extracting CopperKey Points Most copper is extracted by smelting (roasting) copper-rich ores, although our limited supplies of ores are becoming more scarce Copper can be extracted from copper solutions by electrolysis or by displacement using scrap iron. Electrolysis is also used to purify impure copper, e.g.. from smelting Scientists are developing ways to extract copper that use low-grade copper ores. Bacteria are used in bioleaching and plants in phytomining.

C1 3.5: Useful MetalsKey Points The transition metals are found in the central block of elements in the periodic table Transition metals have properties that make them useful for building and making things. For example, copper is used in wiring because of its high electrical conductivity Copper, gold and aluminium are all alloyed with other metals to make them harder.

C1 3.6: Metallic IssuesKey Points There are social, economic and environmental issues associated with exploiting metal ores Plants can remove metals from low-grade ores. The metals can be recovered by processing the ash from burning the plants Recycling metals saves energy and our limited metal ores (and fossil fuels). The pollution from extracting metals is also reduced There are drawbacks as well as benefits from the use of metals in structures.

C1 4.1: Fuels from Crude Oil Key Points Crude oil is a mixture of many different compounds Many of the compounds in crude oil are hydrocarbons- they contain only hydrogen and carbon Alkanes are saturated hydrocarbons. They contain as many hydrogen atoms as possible in their molecules.

C1 4.2: Fractional DistillationKey Points We separate crude oil into fractions using fractional distillation The properties of each fraction depend on the size of their hydrocarbon molecules Lighter fractions make better fuels as they ignite more easily and burn well, with cleaner (less smoky) flames.

C1 4.3: Burning FuelsKey Points When we burn hydrocarbon fuels in plenty of air the carbon and hydrogen in the fuel are completely oxidised. They produce carbon dioxide and water Sulfur impurities in fuels burn to form sulfur dioxide which can cause acid rain Changing the conditions in which we burn hydrocarbon fuels can change the products made In insufficient oxygen, we get poisonous carbon monoxide gas formed. We can also get particulates of carbon (soot) and unburnt hydrocarbons, especially if the fuel is diesel At the high temperatures in engines, nitrogen from the air reacts with oxygen to form nitrogen oxides. These cause breathing problems and can cause acid rain.

C1 4.4: Cleaner FuelsKey Points Burning fuels releases substances that spread throughout the atmosphere Sulfur dioxide and nitrogen oxides dissolve in droplets of water in the air and react with oxygen, and then fall as acid rain Carbon dioxide produced from burning fuels is a greenhouse gas. It absorbs energy which is lost from the surface of the Earth by radiation The pollution produced by burning fuels may be reduced by treating the pollutants from combustion. This can remove substances like nitrogen oxides, sulfur dioxide and carbon monoxide Sulfur can also be removed from fuels before we burn them to prevent sulfur dioxide gas being formed.

C1 4.5: Alternative FuelsKey Points Biofuels are a renewable source of energy that could be used to replace some fossil fuels Biodiesel can be made from vegetable oils There are advantages, and some disadvantages, in using biodiesel  Ethanol is also a biofuel as it can be made from the sugar in plants Hydrogen is a potential fuel for the future.

c1 1.0: Fundemental ideas

C1 2.0: rocks and building materials

c1 3.0: METALS AND THEIR USES

C1 4.0: crude oil and fuels