chemical reactions - term 3 Flashcards
Reactants
The original substances present in a chemical reaction.
Products
The new substance(s) that result from a chemical reaction.
Word Equation
Equation of a chemical reaction, using words, showing the reactants and products.
Chemical Equation
Equation of a chemical reaction, showing the symbols of the elements and molecules involved.
Law of Conservation of Mass
The law states that, in a chemical reaction, the total mass of the reactants is the same as the total mass of the products.
Law of Constant Proportions
The law states that, in chemical reactions, the ratio of the elements is always the same.
Exothermic
Describes chemical reactions that give out heat energy to their surroundings.
Acid
A chemical that reacts with a base to produces a salt and water. Edible acids taste sour. Has a pH of less than 7.
Base
A chemical that reacts with an acid to form a salt and water. Edible bases taste bitter. Has a pH of more than 7.
Alkali
A base that dissolves in water.
Neutral Chemical
A chemical that is neither acidic nor basic. It has a pH of 7.
Indicator
A chemical that changes colour when it reacts with acids or bases.
Universal Indicator
A mixture of indicators that changes colour as the strength of an acid or base changes, indicating the pH of the substance.
pH Scale
A scale of numbers from 1 to 14which show the strength of an acid or base. The numbers from 1 to 6 are acids, 7 is neutral, and 8 to 14 are bases.
Neutralisation Reaction
A reaction of and acid and a base which produces a salt and water.
