Types of Chemical Reactions

Types of Chemical Reactions

Section 3.3

OverviewAt the end of this lesson you will be able to:Predict the products of five types of chemical

reactions, given the reactants and balance the resulting chemical equation

ReviewWhat is the formula for the following

compounds?Magnesium nitratePotassium iodideCalcium phosphateNitrogen trichlorideCarbon dioxide

What ions can combine?How do we find state of ionic compounds?

Types of Chemical Reactions

There are five types of chemical reactions:FormationDecompositionCombustionSingle replacementDouble replacement

What do you think each of these mean? Any guesses?

Formation ReactionsAlso called synthesis reactionSimplest form, two elements combine to form a

compoundElement + element compoundA + B AB

Ex. S8(s) + 8O2(g) 8SO2(g)

Formation ReactionsCan be more complex

Compound + compound compoundEx. CO2(g) + H2O(l) H2CO3(aq)

For more complex formation reactions where one reactant is a metal and one a non-metal, write the ionic compound that would be formed

Decomposition ReactionsBreaking down compounds into its constituent

partsCompound element + elementAB A + B

Only one reactantEx. 2 H2O(l) 2 H2(g) + O2(g)

Combustion ReactionsBurning in the presence of oxygenExothermic? Endothermic?The products are the oxides of the elements

present in the reactants – compounds with oxygen bonded to another element

Generally, the product is most common oxide

Combustion ReactionsBe familiar with these most common oxides:

carbon, then CO2(g) is formedhydrogen, then H2O(g) is formedsulfur, then SO2(g) is formednitrogen, then NO2(g) is formeda metal, then the most common oxide of that metal

is formed

Hydrocarbon CombustionA type of combustion reactionHydrocarbon- substances containing hydrogen

and carbonGeneral formula: CxHy (x= # carbons, y= #

hydrogens)Combine with O2(g) to make two products: CO2(g)

and H2O(g) CxHx + O2 (g) → CO2 (g) + H2O (g)

CH4 (g) + 2 O2 (g) → CO2 (g)+ 2 H2O (g)

Combustion Reactions Other combustion examples:

C3H8(g) + 5 O2(g)→ 3 CO2(g) + 4 H2O(g)

2 Na2S(s) + 3 O2(g)→ 2 Na2O(s) + 2 SO2(g)

 4 Fe(s) + 3 O2(g) → 2 Fe2O3(s)

 4 NH3(g) + 7 O2(g) → 4 NO2(g) + 6 H2O(g)

Single Replacement Reactions

Single element replaces another element in a compound

A + BC B +AC

Mg(s) + 2 AgNO3(aq) 2 Ag(s) + Mg(NO3)2(aq)

Double Replacement Reactions

Element of each of two compounds switch places

AB + CD AD + CB

Be careful!Make sure only combining positive ions with

negative ions (i.e. cannot put positive-positive together)

Positive ions appear first and negative ions second

Questions?

Predicting and BalancingDouble Replacement Reactions:Aqueous lead(II) nitrate and aqueous sodium

iodide are mixed and a yellow precipitate forms. Predict the products, writing out the balanced formula equation, including states

PracticeWrite the formula equation, predict the products, and

balance the following (include states!):When aqueous copper(I) nitrate and aqueous

potassium bromide are mixed, a precipitate forms

Aluminium chloride and sodium hydroxide are mixed, creating a precipitate

Ni(NO3)3(aq) + Na2SO3(aq)

Practice: Single Replacement

Write the formula equation, predict the products and balance the following:

Aluminium metal and copper(II) chloride react together

Chlorine gas is added to a solution of aqueous nickel(III) bromide

Zinc metal is placed into a solution of silver nitrate

Practice: DecompositionPredict the products and balance the following

equations___MgS(s) ___KI(s) ___Al2O3(s) ___NiCl2(s)

Practice: FormationFor the following equations give the product and

balance

sodium + sulfur

magnesium + oxygen

Iron + chlorine

Practice: CombustionComplete and balance each equation:

___CH4(g) + ___O2(g)

___C2H6(g) + ___O2(g)

___C3H8(g) + ___O2(g)

___C6H6(l) + ___O2(g)