Balancing Chemical Equations

Front

What is a balanced chemical equation?

Back

A balanced chemical equation has equal numbers of each type of atom on both sides of the equation, indicating that mass is conserved during a chemical reaction.

Front

What is the law of conservation of mass?

Back

The law of conservation of mass states that mass cannot be created or destroyed in a chemical reaction; it can only change forms.

Front

What are coefficients in a chemical equation?

Back

Coefficients are the numbers placed before the compounds in a chemical equation to indicate the number of molecules or moles of each substance involved in the reaction.

Front

How do you determine the coefficients needed to balance a chemical equation?

Back

To determine coefficients, count the number of atoms of each element on both sides of the equation and adjust the coefficients to make them equal.

Front

What is the first step in balancing a chemical equation?

Back

The first step is to write the unbalanced equation and count the number of atoms of each element on both sides.

Front

What is the significance of the subscripts in a chemical formula?

Back

Subscripts indicate the number of atoms of each element in a molecule; they cannot be changed when balancing equations.

Front

What is the balanced equation for the reaction of ammonium phosphate with lead(IV) nitrate?

Back

4(NH4)3PO4 + 3Pb(NO3)4 → 1Pb3(PO4)4 + 12NH4NO3.

Front

What is the balanced equation for the reaction of phosphorus pentachloride with water?

Back

PCl5 + 4H2O → 5HCl + H3PO4.

Front

What is the balanced equation for the reaction of boron trifluoride with lithium sulfite?

Back

2BF3 + 3Li2SO3 → 1B2(SO3)3 + 6LiF.

Front

What is the balanced equation for the reaction of iron(III) chloride with calcium hydroxide?

Back

2FeCl3 + 3Ca(OH)2 → 2Fe(OH)3 + 3CaCl2.