Balancing Equations

Front

What is the law of conservation of mass in relation to balancing chemical equations?

Back

The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction. Therefore, the number of atoms of each element must be the same on both sides of a balanced equation.

Front

How do you determine if a chemical equation is balanced?

Back

A chemical equation is balanced if the number of atoms of each element is the same on both sides of the equation.

Front

What is the coefficient in a chemical equation?

Back

A coefficient is a number placed in front of a chemical formula in an equation to indicate how many molecules or moles of that substance are involved in the reaction.

Front

How many atoms of oxygen are in the compound Al2O3?

Back

There are 3 atoms of oxygen in the compound Al2O3.

Front

What is the balanced equation for the reaction of aluminum and hydrochloric acid?

Back

2 Al + 6 HCl → 2 AlCl3 + 3 H2.

Front

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

Back

An unbalanced chemical equation has a different number of atoms of one or more elements on each side of the equation, violating the law of conservation of mass.

Front

How do you balance the equation: C3H8 + O2 → CO2 + H2O?

Back

The balanced equation is: C3H8 + 5 O2 → 3 CO2 + 4 H2O.

Front

What is the significance of subscripts in a chemical formula?

Back

Subscripts indicate the number of atoms of each element in a molecule. For example, in H2O, the subscript '2' indicates there are two hydrogen atoms.

Front

What is the first step in balancing a chemical equation?

Back

The first step in balancing a chemical equation is to write down the number of atoms of each element present in the reactants and products.

Front

What is the balanced equation for the combustion of propane (C3H8)?

Back

The balanced equation is: C3H8 + 5 O2 → 3 CO2 + 4 H2O.