Counting atoms, Balancing, Law of Conservation of Mass Review

Front

What is the Law of Conservation of Mass?

Back

The Law of Conservation of Mass states that in a closed system, the mass of the reactants must equal the mass of the products in a chemical reaction.

Front

What does it mean to balance a chemical equation?

Back

Balancing a chemical equation means ensuring that the number of atoms of each element is the same on both sides of the equation.

Front

What are reactants in a chemical reaction?

Back

Reactants are the starting substances that undergo a chemical change in a reaction.

Front

What are products in a chemical reaction?

Back

Products are the substances that are formed as a result of a chemical reaction.

Front

How do you determine the mass of products formed in a reaction?

Back

The mass of the products is equal to the total mass of the reactants, according to the Law of Conservation of Mass.

Front

What is a balanced chemical equation?

Back

A balanced chemical equation has the same number of each type of atom on both sides of the equation.

Front

In the equation C2H4 + 3O2 -> 2CO2 + 2H2O, how many oxygen atoms are on the reactant side?

Back

There are 6 oxygen atoms on the reactant side (3 O2 molecules).

Front

What is the significance of subscripts in a chemical formula?

Back

Subscripts indicate the number of atoms of each element in a molecule.

Front

In NH3, how many hydrogen atoms are present?

Back

There are 3 hydrogen atoms in NH3.

Front

What is the difference between a chemical change and a physical change?

Back

A chemical change results in the formation of new substances, while a physical change does not change the chemical composition of a substance.