Counting Atoms

Front

What is an element?

Back

An element is a pure substance that cannot be broken down into simpler substances by chemical means. Each element is made up of atoms that have the same number of protons.

Front

How do you determine the number of different elements in a chemical formula?

Back

Count the unique chemical symbols in the formula. Each symbol represents a different element.

Front

What is a coefficient in a chemical formula?

Back

A coefficient is a number placed in front of a chemical formula to indicate how many molecules or moles of that substance are present.

Front

How do you calculate the total number of atoms in a chemical formula?

Back

Add the number of atoms of each element present in the formula, taking into account the coefficients.

Front

What does the subscript in a chemical formula indicate?

Back

A subscript indicates the number of atoms of the element that are present in a molecule. For example, in H2O, the '2' indicates there are two hydrogen atoms.

Front

In the formula H2SO4, how many hydrogen atoms are there?

Back

There are 2 hydrogen atoms.

Front

In the formula 4H2O, how many total oxygen atoms are there?

Back

There are 4 oxygen atoms (since there are 4 molecules of H2O, and each has 1 oxygen atom).

Front

What is the total number of atoms in the formula H2SO4?

Back

There are 7 total atoms (2 H + 1 S + 4 O = 7).

Front

How many potassium atoms are in the formula K2SO4?

Back

There are 2 potassium atoms.

Front

What is the difference between a molecule and a compound?

Back

A molecule is a group of two or more atoms bonded together, while a compound is a type of molecule that contains at least two different elements.