Symbolic notation used by chemists to represent a

chemical reaction.

Chemical Equation

In a chemical equation, everything to the left of the

arrow

Reactant – starting materials

In a chemical equation, everything to the right of

the arrow

Product – ending materials

Coefficient

Number in front of a formula. Tells how many formula units are present.

Balanced chemical equation

Demonstrates conservation of mass.

Same # of each element on both sides.

Chemical equations demonstrate conservation

of

mass, charge (& energy)

Reaction with 1 product

Synthesis

Reaction with 1 reactant

Decomposition

Reaction of 1 element with 1 compound to produce a

new element & a new compound

Single Replacement

Reaction of 2 compounds to produce 2 new

compounds.

Double Replacement

Reaction with oxygen. One of the reactants must be

O2.

Combustion

AB A + B

Decomposition

A + B AB

Synthesis

AX + B A + BX

Single Replacement

AX + BY AY + BX

Double Replacement

To predict if a single replacement reaction will

occur,

You must compare the reactivity of the free element with the corresponding element in the compound. Use Table J. If the stand-alone element is above the corresponding element in the compound, the reaction will take place.

Na + MgCl2 ?

Compare Na & Mg (both metals). Na is above Mg in Table J so the rxn occurs.

2Na + MgCl2 2NaCl + Mg

Do the following reactions occur?

• Br2 + HF: Compare Br2 & F2

• Mg + ZnCl2: Compare Mg & Zn

• Na + HCl: Compare Na & H2

• Ag + LiBr: Compare Ag & Li

No

Yes

Yes

No

Stoichiometry Problems

Use the relationship in the balanced equation to predict amounts consumed or produced.Use the equation to set up a ratio.

2Na + 2H2O 2NaOH + H2

How many moles of hydrogen are produced when 4 moles of

sodium reacts completely?

2 Moles of hydrogen!X4

4/2 = X/1 so X = 2