Chemistry I K Semester Review

Chem I | Chem II AP
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Metric System, Exponential Notation, Factor Label and Significant Figures
1)
Solve the following using factor label
a)
250 mm =
m
b)
8.5 L =
mL
c)
525 mg =
lb
[454 g = 1 lb]
2)
How many significant figures are in:
a)
45.03
b)
3500
c)
0.0045
3)
Calculate and round to correct number of sig figs:
a)
(4.25 X 104) (2.1 X 105) =
b)
(3.45 X 106) (7.2 X 103) =
5.3 X 103
Matter and Density
4)
Give one example of a homogenous mixture.
Give one example of a heterogenous mixture.
5)
How many of the following are mixtures? argon, sodium chloride, carbon dioxide, sugar dissolved in water, air
sugar dissolved in water & air
How many of the following are elements? helium, carbon monoxide, carbon, salt water, potassium, water
helium, carbon & potassium
How many of the following are compounds? carbon dioxide, water, gold, iron, sugar dissolved in water
carbon dioxide & water
6)
How many of the following are physical properties? density, mass, color, texture, metal reacts with acid, vinegar reacts with baking soda, volume, boiling point
density, mass, color, texture, volume & boiling point
7)
How many of the following are physical changes? ice melting, iron rusting, baking a cake, evaporation of water, silver tarnishing, cutting paper, burning paper, crushing a sugar cube

ice melting, evaporation of water, cutting paper & crushing a sugar cube

8)
How many of the following are chemical changes? boiling water, tearing paper, vinegar reacts with baking soda, melting gold, dissolving of sugar in water, breaking a stick, freezing water

vinegar reacts with baking soda

9)
Find the density of Substance X if it has a mass of 50.0 g and has a volume of 56 mL
g/mL
D =
m
v
 
50.0 g
56 mL
= 0.89 g/mL
10)
Determine the volume of 25.0 g of mercury which has a density of 13.7 g/mL
mL
D =
m
v
 
13.7
1
=
25.0 g
x
 x = 1.82 mL
11)
A graduated cylinder has a mass of 120.2 g. When 50.0 mL of a liquid are added, the combined mass of the cylinder and liquid is 185.4 g. Calculate the density of the liquid.
g/mL
D =
m
v
 
185.4 g - 120.2 g
50.0 mL
=
65.2 g
50.0 mL
= 1.30 g/mL
12)
A metal cube which has a mass of 25.3 g is placed in a graduated cylinder which contains 20.0 mL of water. The water rises to 23.4 mL. Find the density of the metal.
g/mL
D =
m
v
 
25.3 g
23.4 mL - 20.0 mL
=
25.3 g
3.4 mL
= 7.4 g/mL
13)
Given the following graph of Substance A:
15.0 g of A has a volume of
mL
1.0 mL of A has a mass of
g
Density of A =
g/mL
D =
m
v
 
25 g
2 g
= 12.5
Atomic Structure and the Mole
14)
Which subatomic particles are located in the nucleus?
Which two particles account for almost all of the mass of the atom?
The number of protons = number of
15)
Given: 27Al
# of protons =
# of electrons =
# of neutrons =
Aluminum has an atomic number of 13 which means it has 13 p+ and 13e-. Since the mass number is 27 that means there is 14 no.
Which could be an isotope of 27Al ?
16)
Substance X has 6 protons, 6 electrons and 8 neutrons. Identify the element by writing its element symbol.

Substance X is Carbon - 14

17 a)
45 g Cu =
atoms
45g Cu
×
1 mole
63.5g Cu
×
6.02 x 1023 atoms
1 mole
= 4.3 x 1023 atoms
b)
3.4 mole =
atoms
3.4 mole
×
6.02 x 1023 atoms
1 mole
= 2.0 x 1024 atoms
c)
2.42 moles CO2 =
g
2.42 moles CO2
×
44 g CO2
1 mole CO2
= 106 g
d)
56 g H2O =
molecules
56g H2O
×
1 mole
18g H2O
×
6.02 x 1023 atoms
1 mole
= 1.9 x 1023
e)
8.6 X 1024 atoms Ne =
moles
8.6 x 1024 atoms
×
1 mole
6.02 x 1023 atoms
= 14.29 moles
18)
Given: 23892U
protons =
electrons =
neutrons =
Given: 2511Na
protons =
electrons =
neutrons =
19)
Copper has two naturally occurring isotopes, Cu-63 which represents 69% of all copper atoms and Cu-65 which represents 31%. What is the average mass of a Cu atom?
amu
0.69 x 63 = 43.47
0.31 x 65 = 20.15
43.47 + 20.15 = 63.62 amu
Gas Laws
20 a)
If T ↑, volume

ex: microwave ivory soap

b)
If P ↑, volume

ex: balloon in vacuum

c)
If T ↑, pressure

ex: crushed can

21 a)
A gas has a volume of 5.0 L at 2.0 atm. Find volume at 4.0 atm.
L
P1V1 = P2V2
(2 atm)(5 L) = (4 atm)(x)
x = 2.5 L
b)
A gas at 25° C has a volume of 525 mL. Find volume at 10° C.
mL
* All temperatures should be in Kelvin (add 273)
25°C = 298 K
10°C = 283 K
V1
T1
=
V2
T2
525 mL
298 K
=
x
283 K
x = 499 mL
c)
A gas at 25° C has a pressure of 5.0 atm. Find temperature if pressure is increased to 10.0 atm.
°C
* All temperatures should be in Kelvin (add 273)
25°C = 298 K
P1
T1
=
P2
T2
5 atm
298 K
=
10 atm
x
x = 596 K - 273 = 323°C
d)
Given: 3.2 L of a gas at 3.0 atm and 20° C. Find volume at STP.
L
* All temperatures should be in Kelvin (add 273)
P1V1
T1
=
P2V2
T2
(3 atm)(3.2 L)
293 K
=
(1 atm)(x)
273 K
x = 8.94 L
22)
Given: gaseous N2 and Ar (same conditions of T and P)
a)
Which has the greater velocity?

N2 because the mass is smaller.

b)
Which gas travels faster?

N2 because the mass is smaller.

23)
Butane is collected by water displacement (the gas bubbles up through the water). If the pressure in the tube is 765 torr at 25°C, and water vapor pressure at that temperature is 24 torr, find the pressure of the butane gas.
torr
765 torr - 24 torr = 741 torr
24)
Given: PV = nRT
 
R = 0.0821 L atm / mole K
a)
Determine the number of moles of CO2 if the gas occupies 25 L at 100° C and 3 atm.
moles
100°C = 373 K
PV = nRT
(3 atm)(25 L) = (x)(0.0821 L atm / mole K)(373 K)
x = 2.45 moles
b)
Determine the mass (g) of 21.0 L of CO at 30° C and 2.0 atm.
g
30°C = 303 K
MW =
mRT
VP
28 g =
(x)(0.0821 L atm / mole K)(303 K)
(21 L)(2 atm)
x = 47.27 g
c)
Find the volume of 4.2 g of He at STP.
L
m
v
=
g-mm
22.4 L
4.2 g
x
=
4 g
22.4 L
Liquids
25)
Given: water and air. Which has greater:
a)
Intermolecular forces
b)
Surface tension
c)
Vapor pressure
d)
Boiling point
e)
Evaporation rate
f)
Viscosity
26)
Heating Curve for Water
Heat of Fusion
S → L
Heat of Vaporization
L → G
Specific Heat
L
27)
For water: Heat of fusion = 334 J/g; heat of vaporization = 2260 J/g; specific heat = 4.184 J/g° C
a)
How much energy is needed to melt 25.0 g of ice at 0° C?
J
Q = (25 g)(334 J/g) = 8350 J
b)
How much energy is needed to vaporize 10.0 g of water at 100° C to steam at 100° C?
J
Q = (10 g)(2260 J/g) = 22600 J
c)
How much energy is needed to raise the temperature of 25.0 g of water from 30° C to 65° C?
J
Q = (25 g)(4.184 J/g° C)(35) = 3661 J
d)
Find the specific heat of a metal if 125 g of the metal absorb 550. J of energy and the temperature is raised by 6.0° C.
J/g° C
550 = (125 g)(x)(6° C)
x = 0.73 J/g° C
28)
Refer to the phase diagram below when answering the questions on this worksheet:
a)
What is the normal melting point of this substance?
°C
b)
What is the normal boiling point of this substance?
°C
c)
What phase is present at 0.60 atm and 40°C?
d)
If I had a quantity of this substance at a pressure of 1.25 atm and a temperature of 40° C and lowered the pressure to 0.25 atm, what phase transition(s) would occur?
Solutions
29)
Saturated or Unsaturated?
a)
After dissolving sugar in water, sugar remains on the bottom of the beaker.
b)
A crystal of sugar dissolves after being added to a sugar in water solution.
c)
Solubility of Substance X = 20 g/100 mL of water. 15 g are dissolved/100 mL water.
30)
Determine molarity if 8.0 moles of sugar are dissolved in enough water to make 2.0 L of solution.
M
M =
moles
L
8.0 moles
2 L
= 4 M
31)
How many grams of sugar (g-MM = 342) are needed to make 3.5 L of a 0.25 M solution?
g
M =
moles
L
0.25 M =
x
3.5 L
x = 0.875 moles ×
342 g
1 mol
= 229.25 g
32)
Solubility Curve
a)
Determine the solubility of KCl at 75° C.
g/100g H2O
b)
The solubility of KClO3
as temperature increases.
c)
How many grams of CaCl2 will dissolve in 100 g of water at 20° C?
g
d)
Which substance has the greatest solubility at 10° C?
e)
How many grams of KCl will dissolve in 500 g of water at 75° C?
g
Colligative Properties
33)
What effect does dissolving a solute have on the boiling point of a liquid?
What effect does dissolving a solute in a solvent have on the freezing point of that solvent?
34)
What would be the boiling point for a water solution if the molality of the MgCl2 is 10.0 m? [kb = 0.51°C/m]
° C
ΔT = k × m × i
ΔT = (0.51 °C/m)(10 m)(3) = 15.3°C
100 + 15.3 = 115.3°C
35)
What is the molality of a solution when 250.0 grams of NaCl is dissolved in 750.0 grams of water?
m
250 g NaCl
×
1 mole
58.5 g NaCl
= 4.27 moles
m =
4.27 moles
0.750 kg
= 5.69 m
Nuclear Chemistry
36)
Complete the following nuclear reactions. What type of decay does each reaction represent? (α, β or γ)
a)
23892U →
+
42He
 
b)
13153I → 13154Xe +
 
37)
What is the weakest material that each type of particle cannot go through?
a)
alpha (α) particle
b)
beta (β) particle
c)
gamma (γ) particle