CW3 Chemical reactions involve rearranging atoms to form new substances; during a chemical reaction mass is not created or destroyed
Decomposition reaction
complex compound breaks down into simpler compounds where AB → A + B
polyatomic
containing more than one and especially more than two atoms
rate of reaction
the speed at which a chemical reaction proceeds
Base
a substance that can neutralize the acid by reacting with hydrogen ions
Aerobic respiration
A chemical process in which oxygen is used to make energy from carbohydrates (sugars).
Alkali
A chemical that can dissolve in water, combine with acids to form salts, and make acids less acidic
Neutralisation formula
Acid + Base (Neutralisation reaction) -> Salt + Water
endothermic
Chemical reactions that absorb (or use) energy eg. photosynthesis, melting ice, evaporating liquids
Combustion and equation
Combustion is the burning of fuel in oxygen to provide heat energy. Fuel + O2 -> CO2+H2O +Heat energy
compound
a substance made up of two or more different chemical elements combined in a fixed ratio
enzyme
a biological catalyst and is almost always a protein
Acid
a contributing product containing hydrogen ions
molecule
a group of two or more atoms held together by chemical bonds
Atom
a particle of matter that uniquely defines a chemical element
precipitate
a precipitate is an insoluble solid that emerges from a liquid solution
exothermic
a reaction in which energy is released in the form of light or heat eg. nuclear fission, rusting iron, combustion
Anion
an atom that has more electrons than protons (negative charge)
cation
an atom that has more protons than electrons (positive charge)
Anodising
an electrochemical process that converts the metal surface into a decorative, durable, corrosion-resistant, anodic oxide finish
catalyst
any substance that increases the rate of a reaction without itself being consumed
ion
atoms that bears one or more positive or negative electrical charges
respiration
biochemical process in which the cells of an organism obtain energy by combining oxygen and glucose
law of conservation of mass
in a chemical reaction mass is neither created nor destroyed
pH
quantitative measure of the acidity or basicity of aqueous or other liquid
Precipitation and equation
reactions occur between two aqueous compounds and form a precipitate (solid) and an aqueous solution AB (Compound 1) + CD (Compound 2) -> AD (Precipitate) + BC (Aqueous)
Acid + Metal
salt + hydrogen gas
Acid + Carbonate
salt + water + carbon dioxide
indicator
substances whose solutions change color due to changes in pH eg. Litmus
concentration
the amount of a substance present in a mixture
Corrosion
the gradual destruction of metals due to electrochemical reactions with their surroundings, typically water, salt water or air.
Agitation
the movement of one or more components of a mixture to improve contact
chemical digestion
the process of further degrading the molecular structure of the ingested compounds
combination reaction (synthesis)
when two or more reactants unite to generate a single product
