Test 4 Review

A process by which one or more substances are changed into one or more different substances.

Reactants Products

Chemical Reaction

NaHCO3(s) + HCl(aq) NaCl(aq) + H2O(l) + CO2(g)

Yield sign (s) Solid (l) Liquid (g) Gas (aq) aqueous (dissolved in water)

Symbols

Nitrogen gas and oxygen gas react to produce dinitrogen pentoxide.

2 N2(g) + 5 O2(g) 2 N2O5

Complete the balanced equation

Potassium reacts with water to form potassium hydroxide and hydrogen gas.

2 K + 2 H2O 2 KOH + H2(g)

Synthesis (Combination) Decomposition Single Displacement (Single Replacement) Double Displacement (Double Replacement)

◦ Neutralization Combustion

6 Types of Reactions

Also known as Combination

Two substances (usually elements) comvine to form a new compound.

A + B AB

2 Ca(s) + O2(g) 2 CaO(s)

Synthesis

A compound breaks into its component parts

AB A + B

2 NaCl 2 Na(s) + Cl2(g)

Decomposition

Also known as Single Replacement

An element replaces an anion or a cation of a compound.

A + BC B + AC

A + BC C + BA

Mg(s) + H2SO4(aq) MgSO4(aq) + H2(g)

Single Displacement

Also known as Double Replacement

Cations from two compounds exchange partners

AB + CD AD + CB

BaCl2(aq) + Na2SO4(aq) BaSO4(g) 2 NaCl(g)

Double Displacement

An acid and a base react to form a salt and water.◦ Cation from base pairs with anion from acid to form a salt.◦ Hydroxide from base pairs with hydrogen from acid to

form water.

This is also a Double Displacement (Replacement)

HX + YOH H2O + YX

HCl(aq) + NaOH(aq) H2O(l) + NaCl(aq)

Neutralization

Also known as oxidation◦ Oxygen is a reactant◦ Products always contain carbon dioxide and water◦ Typically produces heat

CxHyOz + O2 CO2 + H2O

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

Combustion

Will nickel replace hydrogen from water?◦ NO

Will lithium replace hydrogen from water?◦ YES

Will lead replace hydrogen from steam?◦ NO

Will magnesium replace hydrogen from steam?◦ YES

Will silver replace hydrogen from acids?◦ NO

Will sodium react with oxygen to form oxides?◦ YES

Practice problems

Will potassium replace zinc within a compound?◦ YES

Will lead replace aluminum within a compound?◦ NO

Will gold replace lithium within a compound?◦ NO

Will iron replace copper within a compound?◦ YES

Practice Problem

Using what you know about types of reactions and the activity series, you can predict products for a reaction.

Ex:

◦Li + AgNO3

◦Na + MgSO4

Predicting Products

LiNO3 + Ag

Mg + Na2SO4

Barium chloride reacts with silver nitrate◦ Type of reaction: Double Displacement◦ BaCl2 + Cu(NO3)2 Ba(NO3)2 + CuCl2

Aluminum oxide decomposes◦ Type of reaction: Decomposition◦ Al2O3 Al + O2

◦ 2 Al2O3 4 Al + 3 O2

More practice

If compounds are soluble, they have the ability to dissolve.

If they dissolve, they dissociate or “break apart” into their ions.

Ex:◦ NaCl Na+1 + Cl-1

◦ BaF2 Ba+2 + 2 F-1

Soluble

2 AgNO3 + H2S Ag2S + 2 HNO3

Q: How many moles of Ag2S will be produced from 3.5 moles of AgNO3?

What happens if grams is involved?◦ Use Molar Mass!

35.3 molAgNO 3

2

2

1

molAgNO

SmolAg1.75 mol Ag2S

Q: How many grams of Ag2S will be produced from 3.5 moles of AgNO3?

A balanced chemical equation tells the mole:mole ratio between different compounds in the equation.

If you are given information about one substance and asked about a different substance, it is a stoichiometry problem.

Tell-tale sign of Stoichiometry

What is the mass of Mg(OH)2 that will react with 1.20g of HCl?

Mg(OH)2 + HCl MgCl2 + H2O

Practice

22

gHCl20.1 gHCl

molHCl

5.36

1

molHCl

OHmolMg

2

)(1 2 2

2

)(1

)(3.58

OHmolMg

OHgMg

0.956g Mg(OH)2