Question

A combination of chemical symbols and numbers that represent a substance is called a(n) ________.

Answer 1

Answer:

• chemical formula

Explanation:

Chemical formulae tells the kind of atoms and their relative proportion in a compound.

For this purpose, chemical formulae use chemical symbols and numbers.

Each element has a chemical symbol. For example, H is used for hydrogen, O is used for oxygen, Na is used for sodium, C is used for carbon.

Numbers as subscripts to the right of a chemical symbol means the number of atoms of that element in the compound.

These are some examples:

Compound           chemical        meaning

                              formula

Sodium chloride     NaCl             the unit fomula NaCl is formed by 1              

                                                     atom of sodium and 1 atom of chlorine.

Water                       H₂O             the molecule H₂O (water) is formed by

                                                     2 atoms of hydrogen and 1 atom of oxygen.

Methane                  CH₄              the molecule CH₄ is formed by 1 atom of

                                                     carbon and 4 atoms of hydrogen.

In those examples you see how chemical symbols and numbers, which is the chemical formulae, are used to represent the substances.