# Unit 3 Review THE MATH OF CHEMICAL EQUATIONS Limiting Reactant Stoichiometry ```Unit 3 Review
THE MATH OF CHEMICAL EQUATIONS Limiting Reactant Stoichiometry
1. Use the following equation to answer the following questions.
2 Na + Cl2 ---> 2 NaCl
a. Starting with 30.1 g of Na and 22.4 g of Cl2, how many grams of NaCl can be made?
Ans ________
b. How many g of excess reactant remain?
Ans ________
c. Afterwards, 17.1 grams of NaCl are produced by the reaction. What is the % yield?
Ans ________
2. A molecule is 87.5% N and is 12.5% H. What is its empirical formula?
Ans ________
If this molecule's formula weight is 48 g/mol, determine its molecular formula: _____________
CHEMICAL EQUATIONS
3. Which set of coefficients balances the equation for
the complete combustion of ethane, C2H6?
__C2H6 + __O2  __CO2 + __H2O
a) 1,3,2,3
c) 2,6,4,5
b) 1,6,2,6
d) 2,7,4,6
4.
When this expression is balanced,
2C3H6 + O2 
CO2 + 6H2O
what is the coefficient of oxygen, O2?
a) 6
c) 12
b) 9
d) 18
5.
During a “titration lab,” an acid was neutralized by
the following reaction:
NaOH + HCl  NaCl + H2O
This reaction would be classified as…
a) synthesis
b) decomposition
c) double replacement
d) single replacement
6.
Which reaction below would be classified as a
decomposition reaction?
a) NaHCO3  NaOH + CO2
b) 2 H2 + O2  2 H2O
c) 2 AgNO3 + Cu°  Cu(NO3)2 + 2 Ag°
d) Ba(OH)2 + H2SO4  BaSO4 + 2 H2O
7.
The complete combustion of ethane, C2H6,
produces
a) C2H5OH
b) CH3COOH
c) CO2 and H2
d) CO2 and H2O
Use the activity series to predict whether the following reactions will occur...
If YES, then write the products -- If NO, then write 'N. R.' (no reaction)
8. Al + FeCl2 --->
___________________
9. Cu(NO3)2 + Ca --->
_____________________
10. Zn + NaCl --->
_____________________
Predict the products:
11. CuSO4 + AgCl ---> __________________
12. C2H6 + O2 ---> ____________________
13. Suppose you made a Micro-Rocket with butane (C4H10) as the fuel. What is the correct ratio of fuel to O2?
14. What gas is formed when Zn metal is mixed with hydrochloric acid, HCl?
a) CO2
c) O2
b) He
d) H2
Nomenclature
The following random compounds need either names or formulas. Help them discover their identity!
1. Cs3P ___________________
2. SiCl4 ___________________
3. platinum (IV) iodate _________
4. calcium nitrite ________
5. stannous chloride ___________
6. HBrO3 ________
7. sulfur trioxide _______________
8. Fe(NO3)2 ___________________
9. (NH4)4C ___________________
10. hydrochloric acid _________
11. mercury (II) oxalate ________
12. CoCO3 _________________
13. CO ___________
14. How many electrons were transferred to make AlCl3? _____
MATTER
1. Which property is always conserved during a
chemical reaction?
a) mass
c) pressure
b) volume
d) solubility
2.
Which one of the following is the correct formula
for aluminum oxide?
a) AlO
c) Al2O3
b) Al6O6
d) Al3O2
3.
What is the name of the compound CF4?
a)
b)
c)
d)
4.
fluorocarbonate
carbon tetrafluoride
tricarbon fluoride
carbon difluorate
Sodium nitride has the formula Na3N. What is the
formula for magnesium nitride?
a) Mg2N
c) Mg3N2
b) Mg3N
d) Mg2N3
5. What is the mass of one mole of aluminum sulfate,
Al2(SO4)3?
a) 630 g
c) 273 g
b) 342 g
d) 123 g
ACIDS, BASES, & SALTS
1. Which of the following is an acid?
a) NaOH
c) HCl
b) NH3
d) H2O
2.
The acid, H2S, is correctly named as:
a) hydrosulfuric acid
b) sulfuric acid
c) dihydrogen sulfide
d) hydrogen(I) sulfide
OXIDATION AND REDUCTION
1. Hydrogen gas was produced according to the following equation:
Zn° + 2 HCl  ZnCl2 + H2
Which chemical is oxidized?
a) Zn°
c) ZnCl2
b) HCl
d) H2
2.
Chemists can make “Trees” by using the reaction:
Cu° + 2Ag+  2 Ag° + Cu2+
Cu°, is _____ electrons and being _____.
a) gaining, oxidized
b) gaining, reduced
c) losing, oxidized
d) losing, reduced
Bonds that hold everything together
Match the following compounds to the three bond types. Each answer may be used once, more than once, or not at all.
C) Covalent Bond
I) Ionic Bond
M) Metallic Bond
___1.
KBr
___6.
CaCl2
___11. ZnI2
___2.
Cu
___7.
Br2
___12. Ag
___3.
CO2
___8.
Na2O
___13. NaCl
___4.
Pb
___9.
SiO2
___14. C(graphite)
___5.
CH4
___10. brass (Cu + Zn)
___15. C3H8
Match the following statements to the three bond types.
Each answer may be used once, more than once, or not at all.
C) Covalent Bond
I) Ionic Bond
M) Metallic Bond
___2.
conducts electricity as a solid
___6.
malleable and ductile
___3.
alternating positive and negative particles
___7.
conducts electricity when dissolved in water
___4.
sharing electrons between two atoms
___8.
involves a transfer of electrons
___5.
positive ions in a “sea of electrons”
___9.
involved in molecules and in network solids
___10. does not usually conduct electricity
Exception?: _______________
11. State whether each molecule below is polar or non-polar. Explain to each other why you made your choice.
Write the Lewis dot structures, geometry, and polarity for the following:
12. O2
13. HF
14. BCl3
15. SO3
16. NO31 -
17. CH3OH
Classify the bond type as non polar, polar, or ionic by calculating ∆EN:
18. KBr
∆EN = ________
bond type = _________
19. CO
∆EN = ________
bond type = __________
20. SiI2
∆EN = ________
bond type = _________
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