test 4 review
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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
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