Science (ch.6 Reactions)

• What are the signs that a chemical reaction has taken place?

  Colour change, temperature change, bubbling, new solid
• What device is used to measure temperature?

  Thermometer
• What are the steps in planning an investigation?

  1. Plan a range of values for variables
  2. Run a head trial investigation to decide intervals
• What causes a chemical change?

  A chemical change is caused by heating
• What is thermal decomposition?

  No new substances are added in thermal decomposition
• What is the general equation for the decomposition of metal carbonates?

  Metal carbonate → metal oxide + carbon dioxide + water
• What does the law of conservation state?

  Mass is never lost or gained in reactions
• What happens to atoms in a chemical reaction?

  Atoms are rearranged but total remains the same
• What is the reaction of zinc with oxygen?

  Zinc + oxygen → zinc oxide
• What is the mass balance in the reaction zinc + oxygen?

  (64g) + (16g) → (80g)
• What do the symbols s, l, g, and aq represent?

  s - solid, l - liquid, g - gas, aq - dissolved
• What is combustion?

  A reaction between a substance and oxygen
• What is a decomposition reaction?

  A larger molecule is broken down into smaller ones
• What is a fuel?

  A material that generates heat
• What is incomplete combustion?

  Burning with not enough oxygen
• What is complete combustion?

  Burning with plenty of oxygen
• What are the products of incomplete combustion?

  Carbon (soot) and carbon monoxide
• What are the consequences of combustion?

  Produces carbon dioxide and carbon monoxide
• What are anomalous results?

  Data that doesn’t fit the patterns
• What is an oxidation reaction?

  A reaction where a substance reacts with oxygen
• What happens when methane reacts with oxygen?

  Methane + oxygen → carbon dioxide + water
• What happens to limewater when it reacts with carbon dioxide?

  Limewater goes cloudy
• What is an exothermic reaction?

  A reaction where thermal energy is released
• What is an endothermic reaction?

  A reaction where thermal energy is absorbed
• What types of substances make good catalysts?

  Transition metals and their compounds
• What do catalysts do in a reaction?

  Reduce the energy needed for a reaction
• What is an independent variable?

  A variable that is changed
• What is a dependent variable?

  A variable that is measured
• What does the rate of reaction refer to?

  How quickly a reaction occurs