PREDICTING PRODUCTS

PREDICTING PRODUCTSChemical Reactions

COMBUSTION REACTIONS

Always have similar reactants: CnHn + O2

Always create the same products: CO2 + H2O

Balance!

C3H8 + O2

CH3CH2OH + O2

CO2 + H2O

CO2 + H2O

SINGLE REPLACEMENT

A + BX AX + B Single element replaces one of the elements in compound

NEVER carry a subscript, only the charge of the ion! Use your polyatomic ion charges Use the periodic table/ periodic table of ions

HNO3 + Zn ???

SINGLE REPLACEMENT

First - decide if the single element forms a cation or an anion and give it the ionic charge. Zinc is the single element and will form a +2 cation.

Second, determine which element in the compound the single element will replace. Cations can only replace cations, anions can only replace anions. (positive replaces positive,

negative replaces negative ions) In this reaction, the hydrogen acts as the cation. Zinc should replace hydrogen.

Next, check the activity series to determine if the reaction will occur.

ACTIVITY SERIES

Activity series - a list of elements based on reactivity.

An element in the activity series can replace any element below it.

Since zinc is replacing hydrogen, zinc must be above hydrogen in the activity series for the reaction to occur. It is, so the reaction occurs.

SINGLE REPLACEMENT

Form products with correct subscripts

Balance equation

2 HNO3 + Zn H2 + Zn(NO3)2

+1 -1 +2 +1 +2 -1

DOUBLE REPLACEMENT

AX + BY AY + BX Two compounds and the partners will switch!

Again…No subscript, only charge!

AgNO3 + NaCl ???

DOUBLE REPLACEMENT

Assign charges to each of the ions.

Positive replaces positive (or negative replaces negative) Compounds MUST have a cation and an anion

Form products and give them the correct subscripts

Balance the equation.

AgNO3 + NaCl ???+1 -1 +1 -1

DOUBLE REPLACEMENT

Ag+1 and Na+1 will switch. Na+1 will compound with NO3-1 and

Ag+1 will compound with Cl-1

AgNO3 + NaClAgCl + NaNO3

+1 -1 +1 -1 +1 -1 +1 -1

DOUBLE REPLACEMENT

AgNO3 + NaClAgCl + NaNO3

Pb(NO3)2 + CuSO4 PbSO4 + Cu(NO3)2

+1 -1 +1 -1 +1 -1 +1 -1

+2 -1 +2 -2 +2 -2 +2 -1

DOUBLE REPLACEMENT

NaOH + FeCl3 ??? NaCl + Fe(OH)3

Pb(NO3)2 + KI ??? PbI2 + KNO3

CaCl2 + NaOH ??? NaCl + Ca(OH)2

DECOMPOSITION

AX A + X Compound breaks apart into two smaller elements/compounds

Acids decompose into water and an oxide. H2CO3 H2O + CO2

Metallic hydroxides (anything with a metal and an OH) decompose to form a metallic oxide and water. Mg(OH)2 MgO + H2O

Metallic carbonates decompose to form a metallic oxide and carbon dioxide. Li2CO3 Li2O + CO2

SYNTHESIS

A + X AX Two simple elements combine to form one compound.

Again…No subscript, only charge!

Na + Cl2 ???

SYNTHESIS

Assign charges to each of the ions (if you have a metal and a nonmetal) to create an ionic compound.

Form the product and give it the correct subscripts.

Balance the equation.

2 Na + Cl2 2 NaCl+1 -1 +1 -1

PREDICTING PRODUCTS ACTIVITY

Match the Reactants with the Products

Take a sheet of paper with you Your name on paper

Write each equation out 4 in group – 2 per group member 3 in group – 3 per group member

Balance the equation

List the reaction Combustion, Decomposition, Single Replacement, Double

Replacement, Synthesis

Staple group together and turn in when finished