Naming Self-Quiz• Mg(NO3)2

• Pb(OH)2

• FeI3

• CI4

• Silver Fluoride• Carbon Tetrachloride• Iron (III) Chloride• Magnesium Hydroxide

Developing Chemical Equations

Chemical EquationsA chemical change involves conversion of

substances into other substances

Reactants Products

Reactants: pure substances that undergo a chemical change

Products: pure substance that is formed in a chemical change (different properties than reactants)

Writing Chemical Equations

3 ways to represent chemical reactions:

Word EquationsSkeleton EquationsBalanced Chemical Equations

Word Equations

Describes a chemical reaction stating the reactants and products

Reactant 1 + Reactant 2 Product 1 + Product 2

Example: hydrogen + oxygen water

Skeleton Equation

Replaces words with chemical formulas to show the chemical composition of the substances

ExampleH2 + O2 H2O

States

The state of any substance in a chemical equation

can be described using one of the following

symbols:State Symbol

Solid (s)Liquid (l)Gas (g)Aqueous (dissolved in water)

(aq)

States

ExampleH2(g) + O2(g) H2O(l)

Law of Conservation of Mass

In any given chemical reaction, the total mass of the products is always the same as the total mass of

the reactants

Examples

4g hydrogen + 32 grams oxygen 36 grams water

103g potassium oxide + 9g water 112g potassium hydroxide

1g carbon + 5.34g sulfur 6.34g carbon disulfide

Balanced Chemical Equations

Shows the units of reactants and products

Demonstrates the law of conservation of mass same number of atoms of each element to appear on both sides of the equation

Coefficient : # placed in front of a chemical formula in a balanced chemical equation

Example 2H2 + O2 2H2O

4 hydrogen + 2 oxygen 4 hydrogen, 2 oxygen

When balancing an equation, you CANNOT add subscripts

Subscripts change the identity of the substance

2H2O = 2 water

H2O2 = hydrogen peroxide

ExamplesWord EquationAluminum + Oxygen Aluminum

Oxide

SkeletonAl(s) + O2(g) Al2O3(s)

Balanced4Al(s) + 3O2(g) 2Al2O3(s)

ExamplesWord EquationAluminum oxide + Calcium Calcium Oxide +

Aluminum

SkeletonAl2O3(s) + Ca(s) CaO (s) + Al(s)

BalancedAl2O3(s) + 3Ca(s) 3CaO (s) + 2Al(s)

ExamplesWord EquationCalcium Chloride + Sodium Sulfate Calcium Sulfate + Sodium

Chloride

Skeleton CaCl2 + Na2SO4 CaSO4 + NaCl

BalancedCaCl2 + Na2SO4 CaSO4 + 2NaCl

Examples

Word EquationCarbon Tetrahydride + Oxygen Gas Carbon Dioxide

+ Water

SkeletonCH4 + O2 CO2 + H2O

BalancedCH4 + 2O2 CO2 + 2H2O

WORK

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