Download Unit 5 Review Assignment Answers

Chemistry Essentials
Unit 5
Chemical Reactions: An Introduction
Review Assignment
Name: ___________KEY_______________ Per.:____ Date: ______
Part I Completion
Fill in the blanks with the word or phrase that best completes the sentence.
1. A chemical equation is balanced by adding _____coefficients_____ as needed.
2. At room temperature, bromine and mercury are ______liquids______.
3. At room temperature, there are _11_ elements that exist as gases. They are
hydrogen, helium, nitrogen, oxygen, fluorine, chlorine, neon, argon, krypton,
xenon, and radon _.
4. The diatomic elements are hydrogen, nitrogen, oxygen, fluorine, chlorine,
bromine, and iodine.
5. When a chemical equation is balanced, there are the same_ types of atoms and the
same__ numbers of each type of atom on __both__ sides of the equation.
6. Balancing a chemical equation satisfies the Law of Conservation of Matter.
7. When writing a chemical equation in standard form, _(g) is used to indicate a gas.
8. When writing a chemical equation in standard form, (l)_ is used to indicate a
liquid.
9. When writing a chemical equation in standard form, (s)_ is used to indicate a
solid.
10. When writing a chemical equation in standard form, (aq)_ is used to indicate a
solution(dissolved in water.)
11. When an atom gains or loses _electrons__, an ion is formed.
12. An anion has more electrons_ than protons_.
13. A cation has more _protons than _electrons__.
14. Ionic compounds are held together by electrostatic interactions.
15. Ionic compounds contain a metal and a(n) nonmetal.
16. The coefficients in a chemical equation are always the smallest whole numbers
possible.
Part II Short Answer
17. A student performed a series of experiments and recorded the information in the
table below. Complete the table.
Experiments
Exp.#
1
2
3
4
5
Description of Experiment
Observations During & After
A clear colorless liquid was placed over a
flame. Bubbles formed in the liquid.
Did a Chemical
Reaction Occur?
NO
Reasons(s)
A clear orange liquid and a blue powder are
mixed together. The result is a clear colorless
liquid.
A silvery solid is placed in a clear blue liquid.
The liquid bubbles furiously and the solid
gradually disappears.
Two clear colorless liquids are mixed. The
beaker becomes very warm to the touch.
YES
Unexpected color
change
YES
Formation of a gas
YES
Heat produced
A clear yellow liquid and a clear colorless
liquid are mixed. The result is a cloudy blue
solution. Upon setting, the solution separates
into a clear colorless liquid and a bright blue
solid.
YES
Unexpected color
change, formation of
a solid
Change in state
Part III Equations
For each of the following, a) underline the reactants and circle the products, b) write a
word equation, c) write and balance a symbolic equation.
17. Hydrogen and bromine react to form gaseous hydrogen bromide.
Hydrogen gas + liquid bromine → gaseous hydrogen bromide
18. Solutions of iron (III) chloride and sodium hydroxide react to form solid iron (III)
hydroxide and a solution of sodium chloride.
Aqueous iron (III) chloride + aqueous sodium hydroxide → solid iron (III)
hydroxide + aqueous of sodium chloride
19. Liquid carbon disulfide reacts with oxygen to produce carbon dioxide gas and
sulfur dioxide gas.
liquid carbon disulfide + oxygen gas → carbon dioxide gas + sulfur dioxide gas
20. A piece of copper is placed in a solution of silver nitrate. Silver metal and a
solution of copper (II) nitrate are formed.
solid copper + aqueous silver nitrate → solid silver + aqueous copper (II) nitrate
21. When heated, ammonium nitrate decomposes to form dinitrogen monoxide gas
and gaseous water.
solid ammonium nitrate → dinitrogen monoxide gas + gaseous water (put ∆ over
arrow)
Balance the following equations.
22. _2__Na(s) + _2_HOH(l) → __2_ NaOH(aq) + _____H2(g)
Na-1
Na – 1 2
2

H-1 2
OH -1 2
H-2
OH - 1 2
23. _____CuCl2(s) + _____Na2SO4(aq) → __2__NaCl(aq) + _____CuSO4(s)
Cu - 1
Cu - 1

Cl - 2
Na - 2
SO4 - 1
Cl – 1 2
Na – 1 2
SO4 - 1
24. _3__Li(s) + _____AuCl3(aq) → _3__LiCl(aq) + _____Au(s)
Li – 1 3
Li – 1 3

Au – 1
Cl – 3
Au - 1
Cl – 1 3
25. _____C10H8(s) +__12__ O2(g) → __10__CO2(g) + __4_H2O(l)
C – 1 10
C -10
H–8
O – 2 24

H-2 8
O – 3 21 24
26. _2__NaN3(s) → _2__ Na(s) + _3__N2(g)
Na – 1 2
N–36

Na- 1 2
N–2 6
27. _____BaCl2(aq) + _____K2CO3(aq) → _____BaCO3(s) + _2__KCl(aq)
Ba - 1
Ba - 1
Cl – 2
Cl – 1 2
K–2
CO3 – 1

K–1 2
CO3 - 1
28. _____H2SO4(aq) + __2__KOH(aq) → _____K2SO4(aq) + __2__HOH(l)
H–2
H–12

SO4 – 1
K–1 2
OH – 1 2
SO4 - 1
K-2
OH – 1 2
29. _____(NH4)3PO4(aq) + _____CrBr3(aq) → _3_NH4Br(aq) + _____CrPO4(s)
NH4 – 3
NH4 – 1 3

PO4 – 1
Cr – 1
Br – 3
PO4 - 1
Cr - 1
Br – 1 3
30. _____Al(s) + __3__CuCl(aq) → _3__Cu(s) + _____AlCl3(aq)
Al – 1
Cu – 1 3
Cl – 1 3
Al - 1

Cu – 1 3
Cl - 3