Questions - Chemistry

1) Can you give the names of different types of chemical reactions
Oxidation - this is when a substance reacts with oxygon releasing energy (heat and light)
Combustion is an oxidation reaction
Rusting is an oxidation reaction (iron + oxygon = iron oxide)
Thermal Decomposition - this is when a substance is heated and breaks down
Neutralisation -

2) What is an Exothermic Reaction ?
This is a chemical reaction that transfers energy to the surroundings
rusting, camp fires, water evaporation, water + acid reacting, nuclear fusion

3) What is an Endothermic Reaction ?
This is a chemical reaction that takes energy from the surroundings
water to ice, cooking an egg, photosynthesis, dissolving salt in water, baking bread

4) What is the name of the scale used to measure how Acid or Alkaline a substance is ?
The PH scale (from 0 to 14)
Substances with a PH less than 7 are called acids (hydrochloric acid)
Substances with a PH more than 7 are called alkaline (sodium hydroxide)
Substances with a PH equal to 7 are considered neutral (water)

5) What is a control variable ?
Something in an experiment you keep the same.

6) What is an independent variable ?
The thing being changed.

7) What is a dependent variable ?
The thing that is measured.