CHEMISTRY
MID TERM EXAM REVIEW
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1. How many atoms of hydrogen are present in 3
moles of acetic acid?
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1. How many atoms of hydrogen are present in 3 moles of
acetic acid?
3 mol Ac x 4 moles H x 6.02 X 1023atoms H
1 mole Ac
1 mole H
= 7.22 X 1024atoms
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2. What is the molecular formula of butane?
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2. What is the molecular formula of butane?
C4H10
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3. How many moles of carbon are present in 2
moles of butane?
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3. How many moles of carbon is present in 2 moles of
butane?
2 mol butane x 4 mol C
1 mol butane
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=
8 mol C
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4. What is the percent composition of ethanol?
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4. What is the percent composition of ethanol?
First find MOLAR MASS
2C = 2 x 12.0 = 24.0
6H = 6 x 1.0 = 6.0
1O = 1 x 16.0 = 16.0
Total
46.0 g/mol
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4. - continued What is the percent composition of ethanol?
Mass of each element / Total x 100 = %
%C = 24.0/46.0 x (100) = 52%
%H = 6.0/46.0 x (100) = 13%
%O = 16.0/46.0 x (100) = 35%
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5. Classify the reactions shown below
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5.Classify the reactions shown below
Decomposition
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5. Classify the reactions shown below
Decomposition
Double replacement
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5. Classify the reactions shown below
Decomposition
Double replacement
Synthesis
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5. Classify the reactions shown below
Decomposition
Double replacement
Synthesis
Single replacement
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6. What number should be written
in front of Na to balance the
equation
Na + Cl2  NaCl ?
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6. What number should be
written in front of Na to balance
the equation
Na + Cl2  NaCl ?
2
2Na + Cl2  2NaCl
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7. What number should be
written in front of Fe in order to
balance
Fe + O2  Fe2O3?
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7. What number should be
written in front of Fe in order to
balance
Fe + O2  Fe2O3?
4
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7. What number should be
written in front of Fe in order to
balance
Fe + O2  Fe2O3?
4
4Fe + 3O2  2Fe2O3
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8.Measure the object with the
ruler to the correct number of
significant figures.
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8. Measure the object with the
ruler to the correct number of
significant figures. 11.65 cm
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8. Measure the object with the
ruler to the correct number of
significant figures. 11.65 cm
Must make ONE estimate smaller than marks.
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9. Classify each as accurate &/ or
precise
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9. Classify each as accurate &/ or
precise
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10. What symbol expresses
uncertainty in a measurement?
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10. What symbol expresses
uncertainty in a measurement?
+/-
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11. Name the compound S3O6
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11. Name the compound S3O6
Trisulfur hexoxide
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12. What is the formula for the
compound that is formed by
magnesium and hydroxide ions?
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12. What is the formula for the
compound that is formed by
magnesium and hydroxide ions?
Mg(OH)2
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13. What is the formula for the
compound that will form between
calcium and phosphate ions?
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13. What is the formula for the
compound that will form between
calcium and phosphate ions?
Ca3(PO4)2
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14. What is the correct formula
for barium oxide?
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14. What is the correct formula
for barium oxide?
BaO
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15. What is the volume of a
mole of gas at STP?
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15. What is the volume of a
mole of gas at STP?
22.4 L
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16. In a chemical reaction, the total
mass of the products compared to
the total mass of the reactants is
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16. In a chemical reaction, the total
mass of the products compared to
the total mass of the reactants is
always the same
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17. Calculate the number of
atoms in 1.40 mol of Ag.
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17. Calculate the number of
atoms in 1.40 mol of Ag.
1.40 mol x 6.02 X 10 23 atoms
1 mol
= 8.43 X 10 23 atoms
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18. Calculate the number of
liters of gas in 1.47 mols at STP
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18. Calculate the number of
liters of gas in 1.47 mols at STP
1.47 mol
x 22.4 L
1 mol
= 32.9 L
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19. In the formula Ca3(PO4)2, the
total number of oxygen atoms is
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19. In the formula Ca3(PO4)2, the
total number of oxygen atoms is
2 X 4 = 8 oxygen atoms
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20. In the formula 3 Mg(NO3)2,
the total number of oxygen
atoms is
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20. In the formula 3 Mg(NO3)2,
the total number of oxygen
atoms is
3 (3 X 2) = 18 oxygen atoms
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21. In the formula 3 Mg(NO3)2,
the total number of atoms is
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21. In the formula 3 Mg(NO3)2,
the total number of atoms is
18 oxygen atoms +
3 Mg atoms +
6 nitrogen atoms
= 27 total atoms
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22. In the expression
3Mg(NO3)2, the number 2 is
known as the ______.
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22. In the expression
3Mg(NO3)2, the number 2 is
known as the ______.
subscript
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23. In the expression 6 Ca3(PO4)2,
the 6 is known as the _____.
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23. In the expression 6 Ca3(PO4)2,
the 6 is known as the _____.
coefficient
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24. What is the name of the
Law that directs us to balance
equations?
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24. What is the name of the Law
that directs us to balance
equations?
The Law of
Conservation of Matter
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25. When oxygen is available,
nitrogen dioxide is produced from
the burning of nitrogen.
Write the word equation for this
reaction.
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25. When oxygen is available,
nitrogen dioxide is produced from
the burning of nitrogen.
Write the word equation for this
reaction.
nitrogen + oxygen  nitrogen dioxide
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25. When oxygen is available,
nitrogen dioxide is produced from
the burning of nitrogen.
Write the word equation for this
reaction.
oxygen + nitrogen  nitrogen dioxide
also acceptable
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26. Give two examples of a
chemical change.
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26. Give two examples of a
chemical change.
Souring milk, burning anything,
cooking, rotting, decaying leaves,
releasing a gas, reacting to…
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27. Classify each of the following
reactions:
2 Mg + O2  MgO
CH4 + O2  CO2 + 2 H2O
AgNO3 + NaCl  NaNO3 + AgCl
H2O  H2 + O 2
AgCl + Cu  CuCl + Ag
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27. Classify each of the following
reactions:
2 Mg + O2  MgO
synthesis
CH4 + O2  CO2 + 2 H2O
combustion
AgNO3 + NaCl  NaNO3 + AgCl double
replacement
H2O  H2 + O2 decomposition
AgCl + Cu  CuCl + Ag single
replacement62
28. Balance each of the following
equations
a. NaCl  Na + Cl2
b. S + Cl2  SCl3
c. K + AgCl  Ag + KCl
d. Ca(OH)2 + HCl  H2O + CaCl2
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28. Balance each of the following
equations
a. 2 NaCl 2 Na + Cl2
b. 2 S + 3 Cl2  2 SCl3
c. K + AgCl  Ag + KCl
d. Ca(OH)2 + 2 HCl  2 H2O + CaCl2
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29. Use the experiment shown in
the figure to answer the questions
a. A gas was given off, collected in a test
tube, and then tested with a burning splint.
A “pop/chirp” was heard. What was the gas?
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29. Use the experiment shown in
the figure to answer the questions
a. A gas was given off, collected in a test
tube, and then tested with a burning splint.
A “pop/chirp” was heard. What was the gas?
What are the reactants?
What type/classification of reaction?
What are products?
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29. Use the experiment shown in
the figure to answer the questions
a. A gas was given off, collected in a test
tube, and then tested with a burning splint.
A “pop/chirp” was heard. What was the gas?
Mg + HNO3 
single replacement
hydrogen + magnesium nitrate
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29. Use the experiment shown in
the figure to answer the questions
a. A gas was given off, collected in a test
tube, and then tested with a burning splint.
A “pop/chirp” was heard. What was the gas?
hydrogen
NOT the magnesium nitrate
ionic compounds are solids
or dissolved (aq) in water
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29. Use the experiment shown in
the figure to answer the questions
b. The substances Mg metal and dilute HNO3,
are called --?
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29. Use the experiment shown in
the figure to answer the questions
b. The substances Mg metal and dilute HNO3,
are called --?
reactants
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29. Use the experiment shown in
the figure to answer the questions
c. Write the correct balanced equation for the
experiment
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29. Use the experiment shown in
the figure to answer the questions
c. Write the correct balanced equation for the
experiment
Mg + 2HNO3  H2 + Mg(NO3)2
diatomic
ionic : charges
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