chemical reactions Flashcards
What is a chemical reaction?
it is when 2 or more elements combine to make a product.
What is a word equation?
a word equation shows the names of the substances in a reaction.
What is a balanced equation?
A balanced equation gives more information about a chemical reaction because it includes the symbols and formulae of the substances involved. There are two steps in writing a balanced equation:
How do you write a balanced equation?
replace the name of each substance with its symbol or formula
use numbers to balance the equation, if it is not already balanced
what is combustion?
it is the process of burning heat.
what is exothermic?
it is a reaction in which energy is given out to the surroundings.
what is endothermic?
Reaction in which energy is taken in from the surroundings. The surroundings then have less energy than they started with, so the temperature falls.
what is reactions?
Substances present at the start of a chemical reaction.
what is acid?
Corrosive substance which has a pH lower than 7. Acidity is caused by a high concentration of hydrogen ions
what is hydrocarbon?
A compound that contains hydrogen and carbon only.
what is limewater?
Calcium hydroxide solution. It turns milky in the presence of carbon dioxide.
what is a product?
A substance formed in a chemical reaction.
what is neutralise?
To be made neutral by removing any acidic or alkaline nature.
what is thermal decomposition?
Type of reaction in which a compound breaks down to form two or more substances when it is heated.
what is catalyst?
Changes the rate of a chemical reaction without being changed by the reaction itself.
