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, multiply the subscript of each element by the number of molecules (if applicable) and sum them up.

Front

How many total atoms are in the compound Al₂(SO₄)₃?

Back

Al₂(SO₄)₃ has 2 Al, 3 S, and 12 O, totaling 17 atoms.

Front

What does a subscript in a chemical formula indicate?

Back

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

Front

In the compound (NH₄)₂CrO₄, how many nitrogen (N) atoms are present?

Back

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

Front

How do you calculate the number of hydrogen (H) atoms in 3(NH₄)₂CrO₄?

Back

Each (NH₄) has 4 H atoms, so 3(NH₄)₂ has 3 x 8 = 24 H atoms.

Front

What is the total number of chlorine (Cl) atoms in 10MgCl₂?

Back

There are 20 chlorine (Cl) atoms in 10MgCl₂ (10 x 2 = 20).

Front

What is the significance of parentheses in chemical formulas?

Back

Parentheses indicate that the enclosed elements and their subscripts are multiplied by the subscript outside the parentheses.

Front

How many oxygen (O) atoms are in the sulfate ion (SO₄)²⁻?

Back

The sulfate ion (SO₄)²⁻ contains 4 oxygen (O) atoms.

Front

What is the total number of atoms in the formula C₆H₁₂O₆?

Back

C₆H₁₂O₆ has 6 C, 12 H, and 6 O, totaling 24 atoms.

Front

How many magnesium (Mg) atoms are in the compound MgCl₂?

Back

There is 1 magnesium (Mg) atom in MgCl₂.