Glossary Flashcards
balanced symbol equation
In a balanced symbol equation, chemical formulae
represent the reactants and products. The equation
shows how atoms are rearranged, and gives the
relative amounts of reactants and products.
chemical reaction
A change in which atoms are rearranged to create new substances.
combustion
A chemical reaction in which a substance reacts quickly with oxygen and gives out light and heat.
conservation of mass
In a chemical reaction, the total mass of reactants is equal to the total mass of products. This is conservation of mass. Mass is conserved in chemical reactions and in physical changes.
decomposition
A chemical reaction in which a compound breaks down to form simpler compounds and/or elements.
discrete
A variable that can only have whole-number values.
endothermic change
An endothermic change transfers energy from the surroundings.
exothermic change
An exothermic change transfers energy to the surroundings.
fossil fuel
A fuel made from the remains of animals and plants that died millions of years ago. Fossil fuels include coal, oil, and natural gas.
fuel
A material that burns to transfer useful energy.
hazard
A possible source of danger.
non-renewable
Some fuels are non-renewable. They form over millions of years, and will one day run out.
oxidation
A chemical reaction in which substances react with oxygen to form oxides.
physical change
A change that is reversible, in which new substances are not made. Examples of physical changes include changes of state, and dissolving.
product
A substance that is made in a chemical reaction.
