Chem

• Indicators change colour depending on whether a substance is acid, alkaline or neutral
• Universal indicator - changes colour at different pH
• Acid - has pH less than 7
• Alkali- substance of a pH of more than 7

  Is a soluble base
• Neutralisation reaction - equal volumes of acid and alkali react together to make neutral salt
• Base : substance with pH more than 7

  A base is insoluble
• Hydrochloric acid produces chloride salt
• Nitric acid produces nitrate salt
• Sulfuric acid produces sulphate salt
• Acid metal reaction : Metal + acid --> salt + hydrogen gas
• Acid base reaction : produces salt +water
• Acid carbonate reaction: produces salt +water +carbon dioxide
• Litmus paper - blue litmus paper turns red in acid, stays blue if neutral/alkaline

  Red litmus paper stays red if neutral/acid, turns blue if alkaline
• Test for carbon dioxide - turns limewater milky when bubbled
• Test for hydrogen - gas burns with squeky pop
• Acid rain : sulfur dioxide is formed when fossil fuels are burned. It dissolves in rain water forming sulfuric acid
• Fossil fuels :formed over million of years at the bottom of the ocean. When burned produces toxic gases
• Nitrogen dioxide - burning petrol causes this gas. This can lead to respiratory diseases
• Carbon dioxide - dissolves in oceans to form carbonic acid, causing coral bleaching and destroying habitats
• Burette measurements - reading on a Burette goes downwards