Counting atoms. Balanced and unbalanced equations

Front

What must be true for an equation to be balanced?

Back

There must be an equal amount of atoms on both sides.

Front

What are the substances called that are present before a chemical reaction?

Back

Reactants.

Front

How many Hydrogen atoms are in 3(NH₄)₂CrO₄?

Back

24.

Front

What is the relationship between the total mass of reactants and products in a chemical reaction?

Back

The mass is the same.

Front

What do the red numbers in a chemical equation represent?

Back

Coefficients.

Front

What is a coefficient in a chemical equation?

Back

A number placed in front of a chemical formula to indicate how many molecules are present.

Front

What is a subscript in a chemical formula?

Back

A small number that indicates the number of atoms of an element in a molecule.

Front

What is the law of conservation of mass?

Back

Mass is neither created nor destroyed in a chemical reaction.

Front

What is a balanced chemical equation?

Back

An equation where the number of atoms for each element is the same on both sides.

Front

What does it mean if a chemical equation is unbalanced?

Back

The number of atoms of one or more elements is not equal on both sides.