Balancing Equations

Front

What are subscripts in a chemical equation?

Back

Subscripts are the small numbers written below and to the right of an element symbol that indicate the number of atoms of that element in a molecule.

Front

What does it mean for a chemical equation to be balanced?

Back

A balanced chemical equation has the same number of each type of atom on both sides of the equation, meaning mass is conserved.

Front

How do you determine if a chemical equation is balanced?

Back

Count the number of atoms of each element on both sides of the equation and compare them.

Front

What is a coefficient in a chemical equation?

Back

Coefficients are the numbers placed in front of compounds in a chemical equation to indicate how many molecules are involved.

Front

What is the total number of atoms in H₂SO₄?

Back

There are 7 atoms in total: 2 hydrogen, 1 sulfur, and 4 oxygen.

Front

Why is the equation H₂ + O₂ → H₂O not balanced?

Back

It is not balanced because there are 2 oxygen atoms on the left and only 1 on the right.

Front

What is the purpose of balancing chemical equations?

Back

Balancing chemical equations ensures that the law of conservation of mass is followed, meaning matter is neither created nor destroyed.

Front

In the equation PCl₅ + ___ H₂O → ___ HCl + H₃PO₄, how many H₂O molecules are needed to balance it?

Back

4 H₂O molecules are needed.

Front

What does the equation CS₂ + 2O₂ → CO₂ + 2SO₂ represent?

Back

This equation represents the combustion of carbon disulfide, and it is not balanced.

Front

What is the significance of the number of atoms in a molecule?

Back

The number of atoms in a molecule determines its properties and how it interacts with other substances.