Download Test 7 Review

Chemistry R: Form TR7.16A
Name ______________________________
TEST 7 REVIEW
Date _________________ Period _____
Test Review # 7
Conservation of Mass. Matter is neither created nor destroyed. During a chemical reaction the mass does not change. A properly written
equation shows conservation of mass. For example, AgNO3(aq) + NaCl(aq) ÿ NaNO3(aq) + AgCl(s).
SILVER NITRATE
AgNO3
Ag = 1 × 108 =
N = 1 × 14 =
O = 3 × 16 =
108
14
48
170
SODIUM CHLORIDE
NaCl
Na = 1 × 23 =
Cl =
1 × 35 =
AgNO3(aq)
+
NaCl(aq) ÿ
170
+
58
=
228
23
35
58
SODIUM NITRATE
NaNO3
Na = 1 × 23 =
N = 1 × 14 =
O = 3 × 16 =
NaNO3(aq)
85
=
SILVER CHLORIDE
AgCl
Ag = 1 × 108 =
Cl =
1 × 35 =
23
14
48
85
+
AgCl(s)
+
143
108
35
143
228
Balancing Equations. The equation at the top of the box to the right does not show conservation of mass.
Starting with two molecules of hydrogen, as shown in the equation at the bottom of the box by writing a
coefficient 2 in front of the hydrogen and forming two molecules of water by writing a coefficient 2 in front
of the water shows conservation. Coefficients are used to balance equations. Coefficients make the number
of atoms of each type the same on the reactant and product side. As a result, coefficients make the mass the
same on the reactant and product side of the equation. Balancing is done by counting the number and type of
atoms on the reactant and product side of the equation and making them equal.
H 2 + O 2 ÿ H 2O
2 + 32 … 18
2H2 + O2 ÿ 2H2O
2(2) + 32 = 2(18)
36 = 36
Moles. A mole is a formula mass expressed
Gram Formula
in grams. (1 mole = 1 gram formula mass).
Substance
Formula Mass
Atomic mass units are too small to measure on
Mass
g
1. GFM =
a laboratory balance, but grams are not. An
mole
carbon
12 amu
12 g
atom of carbon has a mass of 12 amu and a
2.
g
=
GFM
× mole
58 amu
58 g
molecule of glucose has a mass of 180 amu. sodium chloride
g
Each mass represents one particle. Since the (NaCl)
3. mole =
mass ratios in formula masses and gram glucose (C H O )
GFM
180 amu
180 g
6 12 6
formula masses are the same (12 amu:180
amu::12 g:180 g), the ratio of particles must
still be the same (1mole:1 mole). The gram formula mass
(GFM) is the number of grams in 1 mole. This results in the
Sample Problem
mathematical relationships shown above and to the right.
How many moles of oxygen are consumed when 0.6 moles of
hydrogen burns to produce water?
Stoichiometry. Stoichiometry is the branch of chemistry that
2 H2(g) + O2(g) ÿ 2 H2O
Step 1: W r i t e
a balanced
deals with the application of the laws of definite proportions
equation and determine mole
2
1
2
and of the conservation of mass and energy to chemical
the mole ratios from the ratio
activity. It shows the quantitative relationship between
equation
constituents of a chemical reaction. Stoichiometric
known unknown
calculations are based on several assumptions. It is assumed
Step 2: Identify the known and moles 0.6
x
that the reaction has no side reactions, the reaction goes to
the unknown
completion, and the reactants are completely consumed. One
2
1
•
=
Step 3: Set up a proportion and
type of problem that can be solved stoichiometrically is based
0
.
6
mol
x
solve for the unknown
on the mole ratios of a balanced equation. A sample problem
• 2 x = 0.6mol
is shown to the right.
• x = 0.3mol
Chemistry R: Form TR7.16A
Test Review 7
TEST 7 REVIEW
Page 2
ENERGY
Calculating Joules. When you heat a solid, it’s temperature generally goes up.
There is a relationship between heat and temperature, but they are not the same
thing. It would take a lot more energy to heat up the ocean than to warm a cup of
tea. The ocean has a larger mass. It has many more molecules to share energy with.
Mass is not the only thing that influences the way the temperature changes in
response to heat. When the same sun beats down on the beach, the sand gets a lot
hotter than the water. Water has a higher heat capacity than sand. The relationship
between mass, temperature change, specific heat, and energy are shown to the right.
Specific Heat. Some substances are more resistant to temperature change than
others. They have a higher specific heat. The equation for determining specific heat
is shown to the right
Temperature scales. The Celsius scale is based on water. The freezing point of
water is 0EC, while the boiling point of water is 100EC. The Kelvin scale is based
on the Celsius scale with the zero at absolute zero. Absolute zero is the lowest
possible temperature. It is the temperature at which particles of matter stop moving.
Q = mCp ΔT
Q = heat (J)
m = mass in grams
ΔT = change in temperature [ΔT = Tf – Ti]
Tf = final temperature
Ti = starting temperature
Cp = 4.18 J/gEC for water
cp =
Q
m∆ T
Q = joules;
m = mass in grams
ΔT = change in temperature [ΔT = Tf – Ti]
Tf = final temperature (EC)
Ti = starting temperature (EC)
cp = specific heat (J/gEC)
K = EC + 273 and EC = K – 273
Answer the questions below by circling the number of the correct response
1. When the equation H2 + N2 ! NH3 is completely balanced using
smallest whole numbers, the sum of all the coefficients will be (1) 6
(2) 7 (3) 3 (4) 12
2. When the equation H2 + Fe3O4 ! Fe + H2O is completely balanced
using smallest whole numbers the coefficient of H2 would be (1) 1
(2) 2 (3) 3 (4) 4
3. When the equation __C2H4 + __O2 ! __CO2 + __H2O is correctly
balanced, using smallest whole-numbered coefficients, the sum of
all the coefficients is (1) 16 (2) 12 (3) 8 (4) 4
4. When the equation NH3 + O2 ! HNO3 + H2O is completely balanced
using smallest whole numbers, the coefficient of O2 would be (1) 1
(2) 2 (3) 3 (4) 4
5. When the equation __Na(s) + __H2O(R) ! __NaOH(aq) + __H2(g)
is correctly balanced using smallest whole numbers, the coefficient
of the water is (1) 1 (2) 2 (3) 3 (4) 4
6. When the equation __Al(s) + __O2(g) ! __Al2O3(s) is correctly
balanced using the smallest whole numbers, the coefficient of Al(s)
is (1) 1 (2) 2 (3) 3 (4) 4
7. Given the unbalanced equation:
__Al2(SO4)3 + __Ca(OH)2 !__ Al(OH)3 + __CaSO4
When the equation is completely balanced using the smallest
whole-number coefficients, the sum of the coefficients is (1) 15
(2) 9 (3) 3 (4) 4
8. When the equation __ H2 + __ Cl2 ÿ __ HCl is completely balanced
using the smallest whole-number coefficients, the sum of the
coefficients is (1) 1 (2) 2 (3) 3 (4) 4
9. When the equation
__ Ca(NO3)2 + __ H2SO4 ÿ __ CaSO4 + __ HNO3 is completely
balanced using the smallest whole-number coefficients, the sum of
the coefficients is (1) 5 (2) 2 (3) 3 (4) 4
10. When the equation __ Fe + __ Cl2 ÿ __ FeCl3 is completely
balanced using the smallest whole-number coefficients, the sum of
the coefficients is (1) 7 (2) 6 (3) 3 (4) 4
11. When the equation __ Fe + __ O2 ÿ __Fe2O3 is completely
balanced using the smallest whole-number coefficients, the sum of
the coefficients is (1) 15 (2) 9 (3) 7 (4) 4
12. When the equation __ Zn + __ HCl ÿ __ ZnCl2 + __ H2 is completely
balanced using the smallest whole-number coefficients, the sum of
the coefficients is (1) 5 (2) 9 (3) 3 (4) 4
13. When the equation
__ Cu + __ AgCH3COO ÿ __Cu(CH3COO)2 + __ Ag is completely
balanced using the smallest whole-number coefficients, the sum of
the coefficients is (1) 5 (2) 6 (3) 3 (4) 4
14. When the equation __ H2SO4 + __ NaOH ÿ __Na2SO4 + __ H2O is
completely balanced using the smallest whole-number coefficients,
the sum of the coefficients is (1) 5 (2) 6 (3) 3 (4) 4
15. When the equation __ S + __ O2 ÿ __ SO3 is completely balanced
using the smallest whole-number coefficients, the sum of the
coefficients is (1) 15 (2) 9 (3) 7 (4) 4
16. The gram molecular mass of CO2 is the same as the gram molecular
mass of (1) CO (2) C2H6 (3) SO2 (4) C3H8
Chemistry R: Form TR7.16A
TEST 7 REVIEW
17. What is the total mass of iron in 1.0 mole of Fe2O3? (1) 160 g
(2) 72 g (3) 112 g (4) 56 g
18. What is the mass, in grams, of 1.0 mole of (NH4)2S? (1) 50. (2) 54
(3) 64 (4) 68
19. What is the gram atomic mass of the element chlorine? (1) 17 g
(2) 35 g (3) 52 g (4) 70. g
20. The mass in grams of 1.00 mole of CaSO4•2H2O is (1) 172 g
(2) 154 g (3) 136 g (4) 118 g
21. The gram formula mass of Cu is the same as the gram molecular
mass of (1) CO (2) C2H4 (3) SO2 (4) C3H8
22. What is the mass of 2 moles of potassium nitrate [KNO3]?
(1) 101 g (2) 202 g (3) 303 g (4) 404 g
23. What is the mass of 0.5 moles of aluminum oxide [Al2O3]?
(1) 102 g (2) 51 g (3) 26 g (4) 204 g
24. What is the mass of 0.1 mole of silver acetate [AgCH3COO]?
(1) 16.7 g (2) 84 g (3) 167 g (4) 118 g
25. What is the mass of 0.25 moles of calcium sulfate [CaSO4]?
(1) 172 g (2) 154 g (3) 136 g (4) 34 g
26. How many moles are in 447 g of ammonium phosphate [(NH4)3PO4]?
(1) 1 (2) 2 (3) 3 (4) 4
27. How many moles are in 392 g of sulfuric acid? [H2SO4(aq)]? (1) 1
(2) 2 (3) 3 (4) 4
28. How many moles are in 216. g of dinitrogen pentoxide [N2O5]? (1) 1
(2) 2 (3) 3 (4) 4
29. How many moles are in 780 g of tin IV fluoride [SnF4]? (1) 1 (2) 2
(3) 3 (4) 4
30. According to the equation HCl + NaOH ÿ NaCl + H2O, the total
number of moles of HCl that can be neutralized by 2 moles of NaOH
is (1) 1.0 (2) 2.0 (3) 3.0 (4) 4.0
31. Given the balanced equation: NaOH + HCl ! NaCl + H2O
What is the total number of moles of H2O produced when 3 moles of
the product, NaCl, is formed? (1) 1.0 (2) 2.0 (3) 3.0 (4) 4.0
Test Review 7
Page 3
32. Given the reaction: 4Al + 3O2 ! 2Al2O3
How many moles of Al2O3 will be formed when 2.0 moles of Al reacts
completely with O2? (1) 1.0 (2) 2.0 (3) 0.50 (4) 4.0
33. Given the equation: 2C2H6 + 7O2 ÿ 4CO2 + 6H2O
When 1.0 mole of C2H6 is completely burned, the total number of
moles of CO2 produced is (1) 1.0 (2) 2.0 (3) 8.0 (4) 4.0
34. Given the reaction: Cu + 4HNO3 ! Cu(NO3)2 + 2H2O + 2NO2 how
many moles of H2O are produced when 0.5 moles of Cu is
completely consumed? (1) 1.0 mol (2) 2.0 mol (3) 0.5 mol
(4) 4.0 mol
35. Which temperature represents absolute zero? (1) 0 K (2) 0EC
(3) 273 K (4) 273EC
36. At which temperature does a water sample have the highest average
kinetic energy (1) 0EC, (2) 100EC, (3) 0 K, (4) 100 K
37. When 84 joules of heat is added to 2.0 gram of water at 15EC, the
temperature of the water increases to (1) 5.0EC, (2) 15EC,
(3) 25EC, (4) 50. 0 C
38. Which Kelvin temperatures represent, respectively, the normal freezing
point and the normal boiling point of water? (1) 0 K and 273 K (2) 0 K
and 100 K (3) 100 K and 273 K (4) 273 K and 373 K
39. How many joules of heat energy are released when 50 grams of
water are cooled from 70EC to 60EC? (1) 42 joules (2) 209 joules
(3) 2090 joules (4) 4,180 joules
40. The number of joules needed to raise the temperature of 10 grams
of' water from 20EC to 30EC is (1) 42, (2) 84, (3) 418, (4) 167
41. A 5-gram sample of water is heated and the temperature rises from
10EC to 15EC. The total amount of heat energy absorbed by the
water is (1) 105 J, (2) 84 J, (3) 63 J, (4) 21 J
42. At which temperature would the molecules in a one gram sample of
water have the lowest average kinetic energy? (1) 5EC (2) –100EC
(3) 5 K (4) 100 K
43. How many kilojoules of heat energy are absorbed when 100 grams
of water is heated from 20EC to 30EC? (1) 4.2 kJ (2) 42 kJ
(3) 420 kJ (4) 0.42 kJ
Chemistry R: Form TR7.16A
Test Review 7
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2
2
1
4
3
4
2
4
2
Answers
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
3
1
2
1
1
2
3
4
3
3
41.
42.
43.
44.
45.
46.
47.
48.
1
3
1
2
1
1
3
2
48. If 4 grams of water at 1EC absorbs 33.6 joules of heat, the
temperature of the water will change by (1) 1 CE 2) 2 CE (3) 3 CE
(4) 4 CE
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
47. Which Kelvin temperature is equal to –33EC? (1) –33 K (2) 33 K
(3) 240 K (4) 306 K
2
1
2
2
3
4
3
4
2
1
46. When 5 grams of water at 20EC absorbs 10 joules of heat, the
temperature of the water will be increased by a total of (1) 0. 5 CE
(2) 2 CE (3) 10 CE (4) 50 CE
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
45. How many kilojoules of heat are needed to raise the temperature of
500. grams of water from 10.0EC to 30.0EC? (1) 41.8 kJ (2) 105kJ
(3) 209. kJ (4) 168 kJ
1
4
3
2
2
4
2
4
1
1
44. The temperature of a substance changes from -173EC to 0EC. How
many Kelvin degrees does this change represent? (1) 100. (2) 173
(3) 273 (4) 446
Page 4
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TEST 7 REVIEW