Chemical Reactions Definitions

Question 1

chemical reaction

Answer 1

a change in which atoms are rearranged to create new substances.

Question 2

physical change

Answer 2

a change that is reversible, in which new substances are not made.

Question 3

product

Answer 3

a substance that is made in a chemical reaction.

Question 4

reactant

Answer 4

a starting substance in a chemical reaction.

Question 5

combustion

Answer 5

a chemical reaction in which a substance reacts quickly with oxygen and gives out light and heat.

Question 6

decomposition

Answer 6

a chemical reaction in which a compound breaks down to form simpler compound and/or elements.

Question 7

displacement

Answer 7

when a metal takes the place of a less reactive metal in a compound.

Question 8

endothermic reaction

Answer 8

takes energy from the surroundings.

Question 9

exothermic reaction

Answer 9

releases energy to the surroundings.

Question 10

fuel

Answer 10

a material that is burnt for energy.

Question 11

neutralisation

Answer 11

when an acid and base react together to change the pH of a mixture.

Question 12

oxidation

Answer 12

a chemical reaction in which substances react with oxygen to form oxides

Question 13

thermal decomposition

Answer 13

when a compound is broken down using heat alone

Question 14

word equation

Answer 14

a way of representing a chemical reaction simply. the reactants are on the left of the arrow, and the products are on the right. the arrow means reacts to make.

Question 15

hazard

Answer 15

a possible source of danger

Question 16

balanced symbol equation

Answer 16

in a balanced symbol equation, chemical formulae represent the reactants and the products. the relative amount of reactants and products are shown.

Question 17

conservation of mass

Answer 17

in a chemical reaction, the total mass of reactants is equal to the total mass of products. mass is conserved in chemical reactions and in physical changes.