Chemical Reactions and the Conservation of Mass

Statements that indicate the reactants and products in a chemical reaction.

Ex. Iron (s) + chlorine (g)  -> iron (III) chloride (s)

read as:

“Solid iron and chlorine gas react (combine) to produce solid iron (III) chloride”

A skeleton equation uses chemical formulas rather than words to identify the reactants and products of a chemical reaction.

The word equation

Iron (s) + chlorine (g) -> iron (III) chloride (s)

The skeleton equation

Fe(s) + Cl2(g) -> FeCl3 (s)

NOTE: A skeleton equation is not yet “balanced” by coefficients

H₂O (l) -> H₂ (g) + O₂ (g)

Compare the total mass of the reactants and the total mass of the products.

Do all of the chemical reactions given above conformed to the Law of Conservation of Mass?

What does the mass of the reactants and products tell us about the Law of Conservation of Mass? Why?

State the law of conservation of mass.