Unit 8 Packet - Page 1 of 18Honors Chemistry - Unit 5Chapter 8 – Chemical Equations

Quiz on Diatomic Molecules: Tues., Nov. 15thTest Date: Fri., Nov. 26th

VOCABULARY AssignmentUse the Two-column Notes format/strategy to study/complete your vocabulary assignment.

chemical reaction reactants productssingle displacement double displacement decompositionsynthesis combustion subscriptcoefficient activity series

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

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

Unit 8 Packet - Page 2 of 18Unit 5 PROBLEM SET – Chemical 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.

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 18CHEMICAL EQUATIONS AND REACTIONS

Chemical Equation: represents with symbols and formulas the reactants and products

Example:Reactants yields ProductsFe2O3 + 2 Al 2 Fe + Al2O3

Equations must:Represent known facts – all reactants and products must be included Contain correct formulas

Coefficients: numbers in front of compounds/elementsRepresents the number of moles

Subscripts: numbers in the formulasThey are never changed!

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):

Writing & Balancing Equations

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

orHis Brown Clown Found No Oranges Inside

Unit 8 Packet - Page 4 of 18When 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 timebalance 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

2. aluminum carbide reacts with water to produce methane gas (CH4) and aluminum hydroxide

3. Na2SO4 + LiCl Li2SO4 + NaCl

You try:

1. calcium oxide reacts with bromine to make calcium bromide and oxygen

2. Ba(NO3)2 + PbO2 BaO + Pb(NO3)4

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Unit 8 Packet - Page 7 of 18 Unit 8 Packet - Page 8 of 18

Unit 8 Packet - Page 9 of 18 Unit 8 Packet - Page 10 of 18BALANCING CHEMICAL REACTIONS Equation Writing

Balance and ID the following rxns:Balance the following reactions:

1. Zn + H2SO4 ZnSO4 + H2

1. K3PO4 + HCl KCl + H3PO4

2. Na + Br2 NaBr2. Na + HNO3 NaNO3 + H2

3. H2O H2 + O2

3. S + O2 SO3

4. Cl2 + KI KCl + I24. Ca(ClO3)2 CaCl2 + O2

5. HNO3 + LiOH H2O + LiNO3

5. C2H12 + O2 CO2 + H2O6. C3H8 + O2 CO2 + H2O

6. Potassium iodide + lead (II) nitrate potassium nitrate + lead (II) iodide7. Sodium + iodine sodium iodide

8. Zinc + hydrochloric acid zinc chloride and hydrogen gas7. 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 gas8. Mercury (II) oxide mercury + oxygen

Reaction Prediction

1. Tin (II) and copper (II) sulfate9. Calcium + aluminum chloride calcium chloride + aluminum

2. Iron (III) nitrate and sodium chromate

3. Calcium and iodine10. Mercury (I) nitrate + sodium carbonate sodium nitrate + mercury (I) carbonate

4. Magnesium and sulfuric acid

5. Calcium oxide electrolyzed11. Potassium bromide + aluminum nitrate potassium nitrate + aluminum bromide

6. Carbon and oxygen

7. Sodium carbonate and hydrochloric acid12. Calcium phosphate + aluminum sulfate calcium sulfate + aluminum phosphate

8. Iron (II) sulfide electrolyzed

9. Platinum (II) and lead (II) nitrate13. Rubidium + acetic acid rubidium acetate + hydrogen

10. Lithium oxide and water

11. C2H4 + O2

Unit 8 Packet - Page 11 of 18WRITING 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

6. nitrogen gas + lithium metal

7. C4 H8 + O2

8. sodium bromide + oxygen gas

9. copper (II) nitride (heated)

10. potassium metal + water

11. C3 H8 + oxygen gas

12. ammonium sulfate + sodium chloride

13. NiO + S

Unit 8 Packet - Page 12 of 18REACTION 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

Ex’s:

Electrolysis:Ex:

3. Single Displacement (Replacement): 1 element replaces a similar element in a cmpd

A + BX AX + B

Ex’s:

Unit 8 Packet - Page 13 of 18

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

Ex.

Group Practice: ID, Write & Balance the following equations:

1. C2H4 + O2

2. Barium + Copper (II) chloride

3. O2 + Ca

4. PbCl4 + Al(NO3)3

5. CaCl2

Unit 8 Packet - Page 14 of 18Double Displacement Reactions & Solubility Rules:

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

Practice Writing Dissolution of Solids Equations:Write the net ionic equation for the dissolution of the following compounds.

Sample: BaCl2 (s) Ba+1(aq) + 2Cl-1(aq)

a. Na3PO4 (s)

b. K2SO4 (s)

c. KOH (s)

d. CaI2 (s)

e. Mg(NO3)2 (s)

Unit 8 Packet - Page 15 of 18Net Ionic Equations:

Unit 8 Packet - Page 16 of 18Solubility Rules and Net Ionic Equations Worksheet

Steps for writing a net ionic equation1. 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:

AgNO3 + MgCl2

Which of the following compounds are soluble in water? RbOH CrCO3 PbCl2 TiI BaS

Which of the following compounds are insoluble in water? NH3 (g) Ba(OH)2 PbI2 CaSO4 K2SO3

Write net ionic equations for the following reactions: 1.

Ba(NO3)2 + Na2SO4 BaSO4 + 2 NaNO3

KC2H3O2

(NH4)3PO4

Example 2:

HNO3 + Ba(OH)2

You try:

K2S + Al(NO3)3

2. sodium hydroxide + zinc (II) nitrate sodium nitrate + zinc (II) hydroxide

3. PbCl2 + Na2SO4

4. Silver nitrate and calcium bromide

Unit 8 Packet - Page 17 of 185. sulfuric acid and sodium chloride produce hydrochloric acid and sodium sulfate

6. LiOH + H2S

7. aluminum chloride and iron (III) nitrate

8. ammonium chloride + potassium hydroxide potassium chloride + ammonia (g) + water

9. rubidium carbonate + strontium acetate

Unit 8 Packet - Page 18 of 18

Activity SeriesPg 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(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 F

Cl and I Fe and Sr I 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:

Ni(s) + CuCl2(aq)

Zn(s) + Pb(NO3)2(aq)

Cl2(g) + KI(aq)

Cu(s) + FeSO4(aq)

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:

Ca(s) + O2(g)

Ni(s) + O2(g)

Au(s) + O2(g)