Counting Atoms

Front

What is the formula to determine the number of atoms in a compound?

Back

To find the total number of atoms in a compound, sum the products of the coefficients and subscripts for each element in the formula.

Front

In the compound Al₂(SO₄)₃, how many total oxygen atoms are present?

Back

There are 12 oxygen atoms in Al₂(SO₄)₃.

Front

How many nitrogen atoms are in the compound (NH₄)₂CrO₄?

Back

There are 2 nitrogen atoms in (NH₄)₂CrO₄.

Front

What does the subscript in a chemical formula indicate?

Back

The subscript indicates the number of atoms of the element in one molecule of the compound.

Front

How many magnesium atoms are in 10MgCl₂?

Back

There are 10 magnesium atoms in 10MgCl₂.

Front

In the compound 6NaCl, how many sodium atoms are present?

Back

There are 6 sodium atoms in 6NaCl.

Front

What is the total number of atoms in H₂SO₄?

Back

There are 7 total atoms in H₂SO₄.

Front

What is a coefficient in a chemical equation?

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 compound?

Back

Multiply the number of atoms of each element by its subscript and sum them up.

Front

What is the significance of parentheses in chemical formulas?

Back

Parentheses indicate that the enclosed group of atoms is a polyatomic ion and the subscript outside applies to all atoms within the parentheses.