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 O 2. 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 + MgCl 2  ? Compare Na & Mg (both metals). Na is above Mg in Table J so the rxn occurs. 2Na + MgCl 2  2NaCl + Mg

Do the following reactions occur? Br 2 + HF: Compare Br 2 & F 2 Mg + ZnCl 2 : Compare Mg & Zn Na + HCl: Compare Na & H 2 Ag + LiBr: Compare Ag & Li No 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 + 2H 2 O  2NaOH + H 2 How many moles of hydrogen are produced when 4 moles of sodium reacts completely? 2 Moles of hydrogen! X 4 4/2 = X/1 so X = 2