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

A + O 2  Products Combustion

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

F 2 + MgCl 2  ? Compare F 2 & Cl 2 (both nonmetals). F 2 is above Cl 2 in Table J so the rxn occurs. F 2 + MgCl 2  MgF 2 + Cl 2

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

To predict if a double replacement reaction will occur, You must determine the possible products & determine if the reaction goes to completion. The reaction goes to completion if a gas, a solid, or a small covalent molecule (H 2 O) is formed. Use Table F to determine if a precipitate (solid) is formed.

To predict if a double replacement reaction will produce a precipitate … Write formulas for the possible products. Use Table F to determine if a precipitate (solid) is formed. Scan through table F looking for information about the solubility of the products.

Ba(NO 3 ) 2 (aq) + Fe 2 (SO 4 ) 3 (aq)  ? Write formulas for the possible products: Fe(NO 3 ) 3 + BaSO 4 Scan through table F looking for information about the solubility of the products: All nitrates are soluble so Fe(NO 3 ) 3 is aqueous. Most sulfates are soluble except when combined with Ag +, Ca 2+, Sr 2+, Ba 2+, & Pb 2+ so BaSO 4 is solid.

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

Stoichiometry Problems May involve mole-mole relationships. For reactions involving all gases, coefficients in equation also give information about volume-volume ratios.

2Na + 2H 2 O  2NaOH + H 2 How many moles of hydrogen are produced when 4 moles of sodium reacts completely? 2 Moles of H 2 ! X 4 4/2 = X/1 so X = 2 moles

CH 4 (g) + 2 O 2 (g)  CO 2 (g) + 2 H 2 O(g) How many liters of CO 2 are produced when 3 liters of CH 4 reacts completely? 3 Liters of CO 2 ! X 3 3/1 = X/1 so X = 3