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Chemistry
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Unit 7 Review
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Unit 7 Review
This review provides additional practice on the following learning objectives. You should use the document
Unit 7 Learning Objectives to check on your understandings and as a guide to study for the text.
a) write the complete reaction equation (balanced with physical states)
b) provide either macro- or microscopic interpretations to reaction equations
c) describe how reaction proceeds at atomic level (electron transfer and/or molecular break into atoms)
d) identify the reaction type
e) identify observable changes that suggests the direction of energy flow between the reaction and
surroundings; and write the word energy on the correct side to represent the energy being transferred.
f) draw chemical potential energy curve
g) construct energy bar diagrams to keep track of energy during chemical changes; Fill in the title for
each diagram with the word reactants or products; provide reasoning to your bar diagram.
1. When a small piece of sodium metal is dropped into a beaker of water, hydrogen gas and
sodium hydroxide (soluble) are formed. The solution becomes warm.
Chemical equation
including energy
Reaction type:__________________________________
title
Ech curve:
Reasoning for the above diagrams:
Microscopic interpretation of the reaction equation and particle diagrams for before and after reaction.
2. Heating potassium chlorate powder produces potassium chloride and oxygen gas.
Chemical equation
including energy
Reaction type:__________________________________
Macroscopic interpretation of the reaction equation:
Sun
Chemistry
title
Unit 7 Review
Ech curve:
Reasoning for the above diagrams:
3. In the Instant Cold Pack, there are ammonium nitrate pallets and a small pouch of water.
When the pouch is broken, ammonium nitrate dissolves in water and makes the pack cold.
This process can be represented as following:
Add the word energy:
NH4NO3 (s)  NH4+ (aq) + NO3- (aq)
title:
Reasoning for the above diagrams:
4. Solid barium hydroxide is added to a solution of hydrochloric acid to produce barium
chloride solution and water. The test tube feels warm.
Chemical equation
including energy
Reaction type:__________________________________
title
Reasoning for the above diagrams:
Ech curve:
Sun
Chemistry
Unit 7 Review
5. When a mixture of iron filing (fine powder) and sulfur powder is strongly heated to an orange
glow, solid iron(II) sulfide is formed.
Chemical equation
including energy
Reaction type:__________________________________
title
Ech curve:
Reasoning for the above diagrams:
Describe how the reaction proceeds at atomic level:
6. Propane gas (C3H8) burns in a barbeque grill for cooking hot dogs and burgers. Assuming
complete combustion, what products are produced?
Chemical equation
including energy
Reaction type:__________________________________
title
Ech curve:
Reasoning for the above diagrams:
Describe how reaction proceeds at atomic level and draw particle diagrams for before and after reaction.
Sun
Chemistry
Unit 7 Review
7. Calcium carbonate decomposes into calcium oxide and carbon dioxide gas upon heating.
Chemical equation
including energy
Reaction type__________________________________
title
Ech curve:
Reasoning for the above diagrams:
Microscopic interpretation of the reaction equation:
8. When solid ammonium thiocyanate (NH4SCN) is added to a flask with barium hydroxide
solution, the thin layer of water underneath the flask becomes frozen. The reaction products
are ammonia, water and barium thiocyanate. (Hint for identifying reaction type: once
ammonia hydroxide is formed in solution, it immediately decomposes into ammonia gas and water.)
Chemical equation
including energy
Reaction typ:__________________________________
title
Reasoning for the above diagrams:
Macroscopic interpretation of the reaction equation:
Ech curve:
Sun
Chemistry
Unit 7 Review
9. When quicklime (calcium oxide) is dropped into excess water, milk of lime (calcium
hydroxide solid particles suspended in water) is formed and the mixture starts to boil.
Chemical equation
including energy
Reaction type:__________________________________
title
Ech curve:
Reasoning for the above diagrams:
Microscopic interpretation of the reaction equation:
10. When mercury(II) oxide (red calc) is heated, a silvery liquid is formed and a gas is released.
The liquid conducts electricity and the gas re-ignites a glowing wood splint into flame.
Chemical equation
including energy
Reaction typ:;__________________________________
title
Ech curve:
Reasoning for the above diagrams:
Describe how reaction proceeds at atomic level and draw particle diagrams for before and after reaction.
Sun
Chemistry
Unit 7 Review
11. More practice for balancing reaction equations and classifying reaction type
a. Al( ) + CuSO4(aq)  Al2(SO4)3(aq) + Cu( )
b. Sb( ) +
c. KIO3( )  KI( ) + O2( )
d. Li( ) + H2O( )  LiOH(aq) + H2( )
e. H2SO3(aq) + NaOH(aq)  Na2SO3(aq) + H2O(l)
f. AlCl3( )  Al( ) + Cl2( )
g. C4H8O(l) + O2( )  CO2( ) +
h. Al( ) + Pb(NO3)2(aq)  Al(NO3)3(aq) + Pb( )
i. Mg( ) + Br2( )  MgBr2( )
H2O( )
I2( )  SbI3( )
j. HNO3(aq) + Ba(OH)2(aq)  Ba(NO3)2(aq) + H2O(l)
k. Aqueous solutions of ammonium chloride and lead(II) nitrate produce lead(II) chloride precipitate and
aqueous ammonium nitrate.
l. Liquid carbon disulfide burns in oxygen to yield carbon dioxide and sulfur dioxide gases.
m. Iron metal reacts with aqueous silver nitrate to produce aqueous iron (II) nitrate and silver metal.
n. Upon heating, potassium nitrate yields potassium nitrite and oxygen gas.
o. Calcium metal reacts with chlorine gas to produce calcium chloride.
p. Fluorine gas added to aqueous potassium chloride produces aqueous potassium fluoride and chlorine
gas.
q. Phosphorous reacts with oxygen gas to produce solid diphosphorous pentoxide.