Chemistry Laws and Definitions

Question 1

Compound

Answer 1

A compound is a group of two or more different atoms that are attracted to each other by relatively strong forces or bonds. The atoms are combined in definite proportions.

Question 2

Molecular formula

Answer 2

The molecular formula is a concise way of expressing information about the atoms that make up a particular covalent molecular compound. The molecular formula gives the exact number of each type of atom in the molecule.

Question 3

Law of conservation of mass

Answer 3

The total mass of all the substances taking part in a chemical reaction is conserved.

Question 4

Law of constant composition

Answer 4

In any particular compound, all samples of that compound will be made up of the same elements in the same proportion or ratio.

Question 5

Gay-Lussac’s Law

Answer 5

In a chemical reaction between gases, the relative volumes of the gases in the reaction are present in a ratio of small whole numbers if all the gases are at the same temperature and pressure.

Question 6

Empirical formula

Answer 6

The empirical formula is a way of expressing the relative number of each type of atom in a chemical compound. The empirical formula does not show the exact number of atoms, but rather the simplest ratio of the atoms in the compound.

Question 7

Physical Change

Answer 7

A change that can be seen or felt, but that does not involve the break up of the particles in the reaction. During a physical change, the form of matter may change, but not its identity.

Question 8

Chemical Change

Answer 8

The formation of new substances in a chemical reaction. One type of matter is changed into something different.