Science

• Percentage of oxygen in the air 20%
• Other gases in the air 1%
• Carbon dioxide in the air 0.03%
• Chemical test for oxygen: oxygen will relight a glowing splint
• Greenhouse gases: carbon dioxide water methane nitrogen oxide
• Chemical test for carbon dioxide: carbon dioxide will turn limewater cloudy from colour less
• Change in appearance:colour change,solid formed,gas formed
• Change in energy: heat light sound electricity
• What is always made in a chemical reaction

  New substance
• The rate of a chemical reaction means the _ at which a reaction takes place

  Speed
• Decreasing partical size rate of reaction

  Increases
• Increasing temperature Rate of reaction

  Increases
• Increasing contraction ___ rate of reaction

  Increasing
• As particle size decreases surface area

  increases
• Greenhouse gases

  Carbon dioxide water methane nitrogen oxide
• Can speed up or slow down by

  Changing variables
• What is made when fossill fuels are burned

  Carbon dioxide and water
• An acid is a substance which has a ph..

  below 7
• An alkali is a substance which has a ph..

  above 7
• A neutral substance is a substance which has a ph..

  equal to 7
• Name of indicator used to measure pH

  PH paper, digital ph probe ,universal indicator
• Acid + Alkali

  salt and water
• Sulphuric acid + lithium hydroxide =

  lithium sulfate
• Hydrochloride acid + sodium hydroxide=

  Sodium chloride
• Nitric acid + calcium hydroxide =

  Calcium nitrate
• Phosphoric acid + potassium hydroxide =

  Potassium phosphate
• Fossil fuel + oxygen =

  Carbon dioxide + water
• Carbon dioxide is a greenhouse gas. write the definition of a greenhouse gas.

  Gases that trap heat in the atmosphere
• Explain what it mean by global warming

  Global warming is the process by which the temperature of the earths atmosphere gets hotter as a result of increased amounts of greenhouse gases in the atmosphere
• Write the definition of a catalyst

  A catalyst is a chemical which speeds up a reac with out being used up!
• What is the name of the reaction that occurs between an acid and a base neutralisation,
• Write down 4 ways of preventing rusting

  1. Oiling up
  2. Painting
  3. Aloying
  4. Galvanising
• List 5 variables which may affect the voltage in the cell

  1. pair of metal
  2. Concentration
  3. Electrolyte
  4. Temperature
  5. Distance between metals