Chemical Changes

\

Different Types of Chemical Changes interactions

^^Neutralisation^^

• Process when an acid reacts with and alkali
• Salt and Water is formed
• Eg. Hydrochloric acid(acid) reacts with sodium hydroxide(alkali) to form sodium chloride and water

\
^^Thermal Decomposition^^

• Process where a substance is broken down into two or more simpler substances when heated
• Eg. Copper(II) carbonate is heated to form copper(II) oxide and carbon dioxide

\
^^Oxidation^^

• Process where a substance reacts with oxygen

\
^^Browning^^

• Exposed surface of apples turn brown due to reaction with oxygen in the air

\
^^Combustion^^

• Process where a substance reacts with oxygen in the presence of heat, releasing a lot of it in the process
• One or more new substances produced
• Eg. Charcoal(carbon) in a barbecue pit burns in oxygen to form carbon dioxide
• Eg. Combustion of methane gas(natural) to generate electricity in power plants which forms carbon dioxide and water- If combustion is incomplete, produces carbon monoxide, carbon dioxide and water

\
^^Cellular Respiration^^

• Process where living cells of plants and animals take in oxygen to release the energy stored in glucose
• To provide cells with energy to grow and reproduce
• Carbon dioxide and Water are produced

\
^^Rusting^^

• Process where iron reacts with oxygen in the presence of water vapour

\
^^Photosynthesis^^

• Process where green plants make food in the presence of light

\
^^Electrolysis^^

• Chemical decomposition of substances with the passage of an electric current

\
^^Electroplating^^

• Process where a substance is coated with a metal with the passage of an electric current

\

Acids and Alkalis

• Acids- substance that dissolves in water and dissociates (break up) to give hydrogen ions (h+) which is responsible for the properties of an acid
• Alkali- substance that dissolves in water and dissociates (break up) to give hydroxide ions (OH-) which is responsible for the properties of an alkali

\

pH scale

\

@@C H O M@@

\