chemistry

• Describe the test for hydrogen gas

  Use a lighted splint, hear a squeaky pop sound
• Describe the test for carbon dioxide gas


  Turns limewater milky
• Acid + Metal produces


  Salt + Hydrogen
• Acid + Metal Hydroxide (Alkali) produces


  Salt + Water
• Acid + Metal Oxide (Base) produces


  Salt + Water
• Acid + Metal Carbonate produces


  Salt + Water + Carbon Dioxide
• Describe how crystals of soluble salts such as copper(II) sulfate can be prepared from insoluble bases and carbonates


  Add excess copper (II) oxide/ copper (II) carbonate to use up all acid. Then filtration to remove excess base then evaporation of water to form crystals
• What name is given to salts formed from hydrochloric acid?

  Chlorides
• What name is given to salts formed from sulfuric acid?


  Sulfates
• What name is given to salts formed from nitric acid?


  Nitrates
• Describe the test used to identify Sulfate ions


  White precipitate forms when barium chloride solution is added
• Name the apparatus used in a titration


  Burette and pipette
• What are hydrocarbons?


  Hydrocarbons are compounds that contain carbon and hydrogen only
• How was crude oil formed?


  Over millions of years from the remains of simple marine organisms
• What are 'fractions'?


  Fractions are mixtures containing hydrocarbon compounds with different length carbon chains that have similar boiling points and similar chain lengths
• What is produced by the combustion of hydrocarbons and other fuels?

  Carbon dioxide and water
• What are the 3 parts of the fire triangle?

  Fuel heat oxygen
• What is the cracking process used for?


  The breaking of larger fractions that are less useful as fuels, to produce smaller and more useful hydrocarbon molecules including petrol, diesel and alkenes which can be used to make plastics
• What is the general formula for an alkane? CnH?

  CnH2n+2
• What is the general formula for an alkene? CnH?

  CnH2n
• How do we dispose of plastics?

  Burn bury recycle
• How can we test to see if a substance is an alkane or an alkene?


  Bromine water is used in the test for alkenes. It turns from orange/brown to colourless when added to an alkene but there is no change when added to an alkane.
• What are metal ores?

  Ores are minerals found in the Earth's crust and that they contain metal compounds from which these metals can be extracted
• What are the raw materials used in the blast furnace?


  Iron ore - source of iron. Coke - as a fuel and to produce carbon monoxide for the reduction. Limestone - to remove impurities (slag formation when limestone breaks down and reacts with sand from the rocks). Hot air - provides oxygen so that coke can burn
• What is electrolysis?


  Electrolysis is a chemical reaction involving the splitting up of an ionic compound into its ions by passing an electric current through the molten substance
• What is the positive electrode called?

  The anode
• What is the negative electrode called?

  The cathode
• Why is aluminium so expensive?


  Because of the amount of electricity used up in the extraction process by electrolysis
• What is the first stage of Aluminium extraction?


  Alumina (aluminium oxide) dissolves in molten cryolite at a temperature much lower than its melting point, therefore saving energy.
• List the properties of aluminium


  Strong, low density, good conductor of heat and electricity, resistant to corrosion
• List the properties of copper


  Very good conductor of heat and electricity, malleable and ductile, attractive colour and lustre
• List the properties of titanium


  Hard, strong, low density, resistant to corrosion, high melting point
• What is an alloy?


  A mixture made by mixing molten metals
• What other factors that affect the siting of plants?


  A site away from built up areas. A town or city within commuting distance to accommodate the workforce. Good transport links for transporting the product to buyers and a direct electricity supply (a power station close by) in the case of aluminium
• List the properties of metals


  Strong malleable ductile high melting and boiling points good conductors of electricity good conductors of heat shiny high density
• Describe ionic bonding


  Ionic bonding occurs between positive and negative ions which attract each other and bind together to form ionic compounds.
• Why do ionic compound have high melting and boiling points


  Strong forces of attraction between the ions
• Explain why ionic compounds do not conduct electricity when solid but do when molten or in solution


  When solid the ions are held in fixed positions but when molten or dissolved the ions are free to move - the moving ions create an electrical current
• Explain how covalent bonds are formed


  Non-metal atoms share electrons to get a full outer shell
• Explain why covalent compounds have low melting points and boiling points

  There are only weak intermolecular forces between the molecules