List five indicators of chemical change.

A colour change ,A temperature change Gas/bubbles being produced ,A precipitate (solid) forming Light or a new smell being produced

 Describe the green chemistry principle ‘design for degradation’.

Designing products to break down into harmless substances after use, reducing pollution.

. Explain how a balanced chemical equation provides evidence of the Law of Conservation of Mass.

A balanced equation has the same number of each type of atom on both sides, showing that atoms and mass are conserved.

 Write word equations.

 Nitrogen + hydrogen → ammonia ,  Hydrogen + oxygen → water, Calcium carbonate + nitric acid → water + carbon dioxide + calcium nitrate, Calcium carbonate → calcium oxide + carbon dioxide

Compare the conditions required for the reaction of a metal with carbon and an electrolysis reaction.

Metal reactions with carbon need high temperatures, while electrolysis uses electricity to separate compounds into elements.

 Analyse the equation.

2HCl + Mg → MgCl₂ + H₂

Reactants:
Hydrochloric acid and magnesium.

b) Products:
Magnesium chloride and hydrogen.

c) Does it obey the Law of Conservation of Mass?
Yes. There are equal numbers of each type of atom on both sides.

d) Chemical formula of magnesium chloride:
MgCl₂

Three ways to make sodium chloride synthesis greener:

The 2 g may have escaped as a gas or not been collected. Mass was not destroyed; it was conserved.