Download Unit 8 Packet - Page 1 of 18 Honors Chemistry

Unit 8 Packet - Page 1 of 18
Chapter 8 – Chemical Equations
Quiz on Diatomic Molecules: Tues., Nov. 15th
Test Date: Fri., Nov. 26th
VOCABULARY Assignment
Use the Two-column Notes format/strategy to study/complete your vocabulary
assignment.
chemical reaction
single displacement
synthesis
coefficient
Unit 8 Packet - Page 2 of 18
Unit 5 PROBLEM SET – Chemical Equations:
Honors Chemistry - Unit 5
reactants
double displacement
combustion
activity series
products
decomposition
subscript
OBJECTIVES:

 Be able to balance chemical equations using coefficients. 
 Be able to identify and write the five basic types of equations: single displacement,
 double displacement, synthesis, decomposition and combustion. 
 Be able to use correct notation in equations (such as state symbols). 
 Be able to identify the seven diatomic molecules and use them correctly in equations. 
 Be able to use the activity series to write equations 
Follow the instructions for the cover page for Problem Sets.
Show your work on all problems. Credit will not be given without work.
Include units on your answers.
Review Questions:
1. Name the following:
A. FeSO4
B. BaCl2
C. CO
D. NH4NO2
2. Write the formula for the following:
A. diphosphorus trisulfide
B. cobalt (III) carbonate
C. silver sulfide
3. Nicotine, a component of tobacco, is 74.1 percent C, 8.6 percent H and 17.3 percent N
by mass; the molar mass is about 162.5 g. What is nicotine’s empirical formula? Its
molecular formula?
4. A. How many formula units in 78.3 g of lead (II) phosphate?
B. Calculate the molarity of a 1.5 liter solution of 498.6 g of lead (II) phosphate.
5. Calculate the percent composition of aluminum dichromate.
SYMBOLS USED IN CHEMICAL EQUATIONS
(brief descriptions and table listed below)







State symbols (after formula) s, l, g or aq (book uses cr for crystalline solid) 
up arrow (↑) gas 
down arrow (↓) ppt 
reversible rxn 
 squiggly line above arrow = electric current or with e- as shown below
above arrow = heat 
 temp, pressure may be written above arrow 
 catalyst may be written below or above arrow 
Current Unit Material:
6. Write balanced equations for the following reactions:
A. Calcium metal is added to water.
B. A solution of tin (II) chloride is added to a solution of iron (III) sulfate
C. Chlorine gas is bubbled into a solution of lithium iodide.
D. C3H8 is burned in oxygen
7. How is 2Cl different from Cl2 ?
8. Octane, C8H18, is a component of gasoline. Write the balanced equation for the
complete combustion of octane. (extra credit)
9. The poisonous gas, hydrogen sulfide, can be neutralized with a base such as NaOH
producing water and sodium sulfide. A student asked to write a balanced equation for the
reaction wrote the following:
Na2OH(aq) + H2S (g) Na2S (aq) + H2O (l)
A. Is this equation correct?
B. Explain why or why not, and supply the correctly balanced equation if necessary.
Unit 8 Packet - Page 3 of 18
CHEMICAL EQUATIONS AND REACTIONS
Chemical Equation: represents with symbols and formulas the reactants and products
Example:
Reactants
Fe2O3 +
yields
2 Al
Products
2 Fe + Al2 O3
Equations must:
Represent known facts – all reactants and products must be included
Contain correct formulas
Coefficients: numbers in front of compounds/elements
Represents the number of moles
Subscripts: numbers in the formulas
They are never changed!
Unit 8 Packet - Page 4 of 18
When writing equations you must satisfy the law of conservation matter
(matter can not be created or destroyed)
Therefore we must have the same type and number of each atom on each side of the
equation.
BALANCING EQUATIONS: 4 steps:
1. Start with a word equation
2. Convert to a formula equation (don’t forget the diatomic molecules!)
3. Balance with coefficients:
balance each atom one at a time
balance polyatomic ions on each side of the equation as one unit
balance H and O last (they often appear in more than one compound)
4. Check; if coefficients are not the lowest possible; reduce down.
*****Remember NEVER change subscripts*****
Examples:
1. water breaks down into hydrogen and oxygen
Symbols used in equations are on your objective sheet !
WRITING AND BALANCING EQUATIONS
Diatomic molecules: Occur in pairs in their natural state (when they are alone and not ionic, not in
compounds) – Notice there are 7 of these and they make a 7 shape on the PT!!!!!
Memorize!! (quiz):
2. aluminum carbide reacts with water to produce methane gas (CH4) and aluminum hydroxide
3. Na2SO4 + LiCl Li2SO4 + NaCl
You try:
Writing & Balancing Equations
1. calcium oxide reacts with bromine to make calcium bromide and oxygen
Diatomic molecules –
occur in pairs in their natural state
(when they are alone; not in compounds)
I2, Br2, Cl2, F2, O2, N2, H2 (*Quiz*)
I Bring Clay For Our New House
or
His Brown Clown Found No Oranges Inside
2. Ba(NO3)2 + PbO2
BaO + Pb(NO3)4
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BALANCING CHEMICAL REACTIONS
Unit 8 Packet - Page 10 of 18
Equation Writing
Balance and ID the following rxns:
Balance the following reactions:
1. Zn + H2SO4
1.
K3PO4 +
HCl
KCl
+
2.
Na
+
HNO3
NaNO3 +
3.
S
+
O2
SO3
4.
Ca(ClO3)2
5.
C2H12 +
ZnSO4 + H2
H3PO4
2. Na + Br2
NaBr
H2
3. H2O H2 + O2
4. Cl2 + KI KCl + I2
CaCl2
+
O2
5. HNO3 + LiOH H2O + LiNO3
O2
CO2
+
H2O
6. C3H8 + O2
CO2 + H2O
6. Potassium iodide + lead (II) nitrate potassium nitrate + lead (II) iodide
7. Sodium + iodine sodium iodide
8. Zinc + hydrochloric acid zinc chloride and hydrogen gas
7. Iron (III) oxide + carbon carbon monoxide + iron
9. Potassium hydroxide heated yields potassium oxide and water
10. Magnesium and water produce magnesium hydroxide and hydrogen gas
8. Mercury (II) oxide mercury + oxygen
Reaction Prediction
1. Tin (II) and copper (II) sulfate
9. Calcium + aluminum chloride calcium chloride + aluminum
2. Iron (III) nitrate and sodium chromate
3. Calcium and iodine
10. Mercury (I) nitrate + sodium carbonate sodium nitrate + mercury (I) carbonate
4. Magnesium and sulfuric acid
5. Calcium oxide electrolyzed
11. Potassium bromide + aluminum nitrate potassium nitrate + aluminum bromide
6. Carbon and oxygen
7. Sodium carbonate and hydrochloric acid
12. Calcium phosphate + aluminum sulfate calcium sulfate + aluminum phosphate
8. Iron (II) sulfide electrolyzed
9. Platinum (II) and lead (II) nitrate
13. Rubidium + acetic acid rubidium acetate + hydrogen
10. Lithium oxide and water
11. C2H4 + O2
Unit 8 Packet - Page 11 of 18
WRITING CHEMICAL EQUATIONS
Write balanced equations for the following reactions after identifying the type of reaction.
1.
aluminum sulfate + calcium phosphate
2.
magnesium chloride + manganese (III) nitrate
3.
Hydrogen gas + oxygen gas
4.
Strontium metal + copper (II) nitrate
5.
copper (II) oxide + sulfuric acid
Unit 8 Packet - Page 12 of 18
REACTION TYPES
1. Synthesis: (or composition):
2 or more substances combine to form 1 new substance
A + X AX
Ex’s:
2. Decomposition:
A single substance produces 2 or more simpler substances
AX A + X
6.
nitrogen gas + lithium metal
7.
C4 H8 + O2
8.
sodium bromide + oxygen gas
Electrolysis:
Ex:
9.
copper (II) nitride (heated)
3. Single Displacement (Replacement):
1 element replaces a similar element in a cmpd
10.
potassium metal + water
11.
C3 H8 + oxygen gas
12.
ammonium sulfate + sodium chloride
13.
NiO + S
Ex’s:
A + BX AX + B
Ex’s:
Unit 8 Packet - Page 13 of 18
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Double Displacement Reactions & Solubility Rules:
4. Double Displacement (Replacement):
The ions of 2 cmpds switch places to form 2 new cmpds.
AX + BY AY + BX
*often one of the new cmpds will be a ppt.
Ex’s:
5. Combustion:
When a substance combines with oxygen releasing a large amount of energy in the
form of light and heat.
Often combustions involve a hydrocarbon : cmpd containing C and H
CxHy + O2
CO2 + H2O
Solubility Rules:
Answer the following questions in the space provided.
1. Use your solubility rules to determine if the following substances are soluble (S) or
insoluble (I) in water.
a. NaC2H3O2
f.
K3PO4
b. Li2SO4
g. CaCO3
c. Barium hydroxide
h. NaCl
d. AgCl
i.
PbI2
e. MgBr2
j.
HNO3
Ex.
Group Practice: ID, Write & Balance the following equations:
1. C2H4 + O2
Practice Writing Dissolution of Solids Equations:
Write the net ionic equation for the dissolution of the following compounds.
Sample: BaCl2 (s)
2. Barium + Copper (II) chloride
a. Na3PO4 (s)
b. K2SO4 (s)
3. O2 + Ca
c. KOH (s)
4. PbCl4 + Al(NO3)3
d. CaI2 (s)
e. Mg(NO3)2 (s)
5. CaCl2
Ba+1(aq) + 2Cl-1(aq)
Unit 8 Packet - Page 15 of 18
Net Ionic Equations:
Steps for writing a net ionic equation
1. Write a balanced equation.
2. Use your solubility rules to determine solubility and break soluble compounds into ions (with
charges!). Leave insoluble compounds together without any charges!
3. Cancel out spectator ions – if everything cancels write no net reaction.
4. Write the final equation – include state symbols!
Example 1:
Unit 8 Packet - Page 16 of 18
Solubility Rules and Net Ionic Equations Worksheet
Which of the following compounds are soluble in water?
RbOH CrCO3 PbCl2 TiI BaS
KC2H3O2
Which of the following compounds are insoluble in water?
NH3 (g) Ba(OH)2 PbI2 CaSO4 K2SO3
(NH4)3PO4
Write net ionic equations for the following reactions: 1.
Ba(NO3)2 + Na2SO4 BaSO4 + 2 NaNO3
AgNO3 + MgCl2
2. sodium hydroxide + zinc (II) nitrate sodium nitrate + zinc (II) hydroxide
Example 2:
HNO3 + Ba(OH)2
3. PbCl2 + Na2SO4
You try:
K2S + Al(NO3)3
4. Silver nitrate and calcium bromide
Unit 8 Packet - Page 17 of 18
Unit 8 Packet - Page 18 of 18
5. sulfuric acid and sodium chloride produce hydrochloric acid and sodium sulfate
Activity Series
Pg 265-267
1. What is the activity series
2. Where are the most active elements found in the series?
3. Look at the sample Questions 8-6 on pg 266 then do the practice questions
4. Do the section review 1-2 on page 267.
Activity Series Practice
6. LiOH + H2S
(Use the series for single displacement reactions or synthesis reactions with oxygen):
I. Based on the activity series of metals and halogens, circle the element within each pair that is more likely to
replace the other in a compound?
K and Na
Al and Ni
Bi and Cr
Cl and I
Fe and Sr
I and F
Cl and F
Au and Ag
II. Using the activity series of metals and halogens, predict whether each of the possible reactions listed
below will occur. For the reactions that will occur, write the products and balance the equation:
7. aluminum chloride and iron (III) nitrate
Ni(s) + CuCl2(aq)
Zn(s) + Pb(NO3)2(aq)
Cl2(g) + KI(aq)
Cu(s) + FeSO4(aq)
8. ammonium chloride + potassium hydroxide potassium chloride + ammonia (g) + water
Ba(s) + H2O(l)
Na2SO4(aq) + Ba(NO3)2(aq)
CuCl2(aq) + Mg(NO3)2(aq)
III. Use the activity series to predict whether each of the following synthesis reactions will occur, and write
the chemical equations for those predicted to occur:
9. rubidium carbonate + strontium acetate
Ca(s) + O2(g)
Ni(s) + O2(g)
Au(s) + O2(g)