CP Chemistry Semester 1 Final Test Review
1. Know the symbol and the power of 10 for the following metric prefixes:
A. Mega M 106
D. deka da
101
G. milli m 106
3
-1
B. kilo
k 10
E. deci
d
10
H. micro µ 10-6
C. hecto h 102
F. centi cm
10-2
2. Metric Conversions: Give the value of the following in the units indicated.
a. 6.92 cm = ___0.0692___ m
e.
934 µm = ___0.934____ mm
b. 8 dag = _______800___ dg
f.
550 mL = ____0.55____ L
c. 35 km = ___3,500,000___ cm
g.
6,450,000 mg = _6.450_kg
d. 520 ml = _____0.52_____ L
h.
0.075 g = ___75____ mg
Problems: Calculate the following using correct units and significant digits.
3. A metal has a volume of 8.4 mL and a mass of 32.0 g. What is its density?
4. A solid object has a density of 7.00 g/mL and a volume of 12.0 mL. What is its mass?
5. An object has a density of 9.0 g/mL and a mass of 41.2 g. What is its volume?
6. Be able to read and interpret data off a line graph.
30
20
10
Mass in grams
40
50
MASS v. VOLUME FOR SAMPLES OF
SUBSTANCE X
5
10
15
20
25
30
35
3.8 g/mL
84.0 g
4.6 mL
a. If the mass is 30 grams,
what is the volume? 15 mL
b. What is the mass if you
have 10 mL of substance X?
20 g
c. Calculate the approximate
slope of the line. y/x
Slope = (30-20)/(15-10) = 2
d. Calculate the approximate
density of the substance X.
density = slope of mass v.
volume graph! = 2 g/mL
(calculated in question c.)
Volume in mL
7. Explain the difference between a homogeneous mixture (solution) and a heterogeneous mixture. Give an
example of each.
Heterogeneous Mixture : A mixture that does not blend smoothly throughout – Sand and water
Homogeneous Mixture: A mixture that has constant composition throughout – salt and water
8. Explain the difference between a physical change and a chemical change. Give an example of each.
Physical Change : A change in which no new substances are formed – melting, boiling, distillation,
crystallization, dissolving,
Chemical Change: New substances are formed – combustion, burning, decomposition
9. Conservation of mass problems (mass of reactants = mass of products):
a.
Water is decomposed into hydrogen and water. If 10.0 grams of hydrogen and 79.5 grams of
oxygen are collected, how much water did you start with?
10.0 g hydrogen + 79.5 g oxygen = 89.5 g product = 89.5 g reactant (water)
b.
If 25 grams of sodium reacts with chlorine to form 99 grams of salt (NaCl). How many grams of
chlorine reacted?
Reactants: 25 g sodium + X g chlorine
Products: 99 g salt (sodium chloride)
25 g + X g = 99 g
X = 99 g -25 g = 74 g chlorine
10. What are the differences in the atomic number, atomic mass and mass number?
Definition
How to calculate
Atomic
number
The number of protons in an element.
It determines what element it is. In a
neutral atom, atomic number also
equals the number of electrons. ON
THE PERIOIC TABLE.
# p+ (or # e- in a neutral
atom)
Mass
number
The mass of a specific isotope
p+ + n0
Atomic
mass
The weighted average mass of all
naturally occurring isotopes. ON
THE PERIODIC TABLE.
Weighted average of
mass number and
percent abundance of all
isotopes.
11. What is the definition of an isotope? Why do isotopes of the same element (ex. carbon-12, carbon-13,
carbon-14) have different mass numbers?
An isotope is an element with different number of neutrons.
Isotopes of the same element have different mass numbers because they have different numbers of
neutrons (mass number = #p+ + #n0)
12. Which isotope is the standard for the atomic mass unit (amu)? 12 amu = mass of 1 carbon-12 atom (1
amu = 1/12 carbon-12 mass number)
13. Know how to calculate the number of protons, neutrons and electrons in an isotope when given its mass
number and atomic number.
Element
atomi
c
numb
er
mass
numb
er
proto
ns
neutro
ns
electro
ns
Isotope
name (using
name)
Copper (Cu)
29
64
29
35
29
Copper-64
Neon (Ne)
10
21
10
11
10
Neon-21
Zinc (Zn)
30
65
30
35
30
Zinc-65
Magnesium
(Mg)
12
26
12
14
12
Magnesium26
Isotope
name
(using
symbol)
14. In a chemical reaction, what changes in the atom and what is formed?
Electrons are shared, gained or lost and a new compound is formed
In a nuclear reaction, what changes in the atom and what is formed?
The nucleus of an atom changes and a new element is formed
15. Know that the forms of natural radioactivity are alpha, beta, and gamma.
symbol
Mass (amu)
charge
Alpha α
4
2+
Beta β
0
1-
Gamma γ
0
0
16. Which form of radiation has the lowest energy (ex. can be stopped by paper)? alpha
Which form has the highest energy (ex. will pass through your body and several feet of concrete)?
gamma
17. Know how to balance a nuclear reaction selecting the correct particle.
What particles would you use to balance the following nuclear reactions?
A.
(a)
(b)
(c)
B.
(a)
(b)
(c)
C.
(a)
(b)
(c)
18. Use the following data table on the isotopes of element “X” to answer Questions A-C listed below:
Percent
CALCULATE:
Isotope
Mass in amu
Abundance %
(Mass number) X (% abundance)/100
X-20
19.992
90.48
18.089
X-21
20.994
0.2700
0.0566
X-22
21.991
9.250
2.861
Weighted average atomic mass
20.18
(SUM OF CALCULATED VALUES):
Weighted avg. atomic mass = (Mass x
A.
B.
19.
)X-20 + (Mass x
)X-21 + (Mass x
)X-22
What is the weighted average atomic mass of element “X”?
20.18 amu
Using the periodic table what is the identity and atomic number of element “X”? Neon, 10
Assume the following three isotopes of element Z exist: Z-248, Z-252, and Z-259. If the atomic mass of Z
is 258.63 amu, which of these isotopes is most abundant? Since the atomic mass is the weighted
average, the most abundant will be the isotope with the mass number closest to the atomic mass: Z259.
20.
Give the (1) electron configuration (2) noble gas shorthand and (3) orbital filling diagram for the
following elements.
a.
Sulfur (atomic number 16)
1s22s22p63s23p4
[Ne]3s23p4
1s
21.
22.
2s
2p
3s
b.
Copper (atomic number 29)
1s
2s
2p
3s
3p
1s2 2s2 2p6 3s2 3p6 4s2 3d9
3p
4s
[Ar]4s2 3d9
3d
Give the Lewis electron dot diagrams for the following elements.
A. Mg
Mg
D. F
F
B.
K
K
E. O
C.
Ge
Ge
F. B
O
B
Periodic Table Organization
A. The periodic table is arranged by increasing atomic number.
B. Rows on a periodic table are called periods. Columns on a periodic table are called groups or families.
C. Properties of elements in the same period change (increase or decrease) as you move left to right or
right to left and repeat as you move from one to the next.
D. Properties of elements in a group or family are similar.
E. All atoms of the same element contain the same number of what particle? Protons
F. Identify the location of these groups or families: Alkali Metals (Group 1A) Alkaline Earth Metals
(Group 2A) Halogens (Group 7A) Noble Gases (Group 8A)
G. Given the electron configuration of the atom, identify the location of the element on the periodic table:
i. [He]2s22p4
ii. [Kr]5s2
iii. [Ne]3s23p6iv. [Ar] 4s1 v. [Ne]3s23p5
i. Oxygen, Atomic Number 8, Period 2, Group 6A, Nonmetal
ii. Strontium, Atomic Number 38, Period 5, Group 2A (Alkaline Earth Metals), Metal
iii. Argon, Atomic Number 18, Period 3, Group 8A (Noble Gases), Nonmetal
iv. Potassium, Atomic Number 19, Period 4, Group 1A (Alkali Metals), Metal
v. Chlorine, Atomic Number 17, Period 3, Group 7A (Halogens), Nonmetal
23.
Periodic Table Trends
Know the definitions of each property and the general trends by column and row for:
Electronegativity: Attraction of an atom for electrons
Ionization Energy: Energy required to remove an electron from an atom
Atomic Size (atomic radius): Distance between the center of an atom to the outer edge of the
electron cloud (measured as half the distance between two nuclei)
Ionic size (ion radius): Distance between the center of an ION (WHICH HAS LOST OR GAINED
ELECTRONS) to the outer edge of the electron cloud
A. Identify which of the element in each pair has the LARGER atomic radius:
a. K and Sc
b. Cl and I
c. Ca or Ga
d. Se or O
24.
25.
26.
Electronegativity and Ionization Energy
Electronegativity and Ionization
Energy
Atomic Size and Ionic Size
B. List the elements in order of INCREASING electronegativity:
a. O, S, Se: Se, S, O
b. Al, Cl, P: Al, P, Cl
c. Ca, Mg, Sr: Sr, Ca, Mg
C. Which of these elements has the LOWEST and which has the HIGHEST ionization energy?
Fr, Rn, He or H:
Fr has the lowest ionization energy; He has the highest.
Atomic Size and Ionic Size
How many electrons does a neutral atom have? The same number as the number of protons (atomic
number)
An ion is an atom that has gained or lost electrons in order to become more stable; by achieving the noble
gas configuration.
Complete the table for the ATOMS and IONS of these elements:
Element
Element
Symbol
Atomic
Number
# Valence
Electrons in
the Atom
Total
Number of
Electrons in
an Ion
10
Ion symbol
2
Total
Number of
Electrons in
an Atom
12
Magnesium
Mg
12
Oxygen
O
8
6
8
10
O2-
Phosphorus
P
15
5
15
18
P3-
Aluminum
Al
13
3
13
10
Al3+
Iodine
I
53
7
53
54
I-
Lithium
Li
3
1
3
2
Li+
27.
Mg2+
A metallic bond occurs between what types of elements? Two or more metals
A metallic bond is the attraction between positively charged metal cations and negatively charged
free-floating electrons (“sea of electrons”).
28.
29.
30.
31.
32.
An ionic bond forms between what types of elements? A metal and a nonmetal
An ionic bond is the attraction between positively charged metal cations and negatively charged
anions. Electrons are transferred from the metal (cation) to the nonmetal (anion).
A molecule has a covalent bond and forms between what types of elements? Two or more nonmetals
The bond in a molecule occurs when electrons are shared.
A chemical formula tells you how many of each atom are in the compound, as indicated by subscripts.
MgCl2 means 1 magnesium and 2 chlorine atoms in the compound.
CCl4 means 1 carbon and 4 chlorine atoms in the compound.
Complete the tables below:
Compound Name
Ionic Compound or Molecule?
Chemical Formula
Iron (III) Sulfate
Ionic
Fe2(SO4)3
Disulfurpentoxide
Molecule
S2O5
Aluminum Sulfide
Ionic
Al2S3
Trinitrogenmonofluoride
Molecule
N3F
Chemical Formula
Ionic Compound or Molecule?
Compound Name
NiCl3
Ionic
Nickel (III) chloride
P3O4
Molecule
Triphosphorus tetroxide
CBr4
Molecule
Carbon tetrabromide
BeF2
Ionic
Beryllium fluoride
Recognize the correct Lewis Dot structures for molecules:
The electron dot formula for hydrogen sulfide, H2S has 8 valence electrons. C is the correct structure
The electron dot structure for CN- has 10 valence electrons. III is the correct answer
33.
Using the electronegativities below determine the type of bond that would form between these:
Cl: 3.16 O: 3.5
Na: 0.93
P: 2.19
Cl-P
0.97
Polar
Covalent
33.
Na-Cl
2.23
Ionic
Na-O
2.57
Ionic
Cl-Cl
0.0
Nonpolar
Covalent
Balance the following chemical equations:
A.
1 C3H8 + 5 O2  3 CO2 + 4 H2O
B.
2 Al + 6 HCl  2 AlCl3 + 3 H2
C.
Silver nitrate and copper metal react to form copper (II) nitrate and silver metal
2 AgNO3 + 1 Cu  1 Cu(NO3)2 + 2 Ag
D.
Tetraphosphide and dioxide react to form diphosphorus trioxide
1 P4 + 3 O2  2 P2O3
34.
Why don’t we change subscripts when we balance chemical equations?
If you change the subscript it changes the compound. (example: O2 is oxygen gas but O3 is ozone).
We only use coefficients in front of the formula to balance equations.
35.
Balance the following equations and indicate the type of reaction taking place:
a)
3 Ca(OH)2 + 1 Al2(SO4)3  3 CaSO4 + 2 Al(OH)3
Type of reaction: double displacement
b)
3 Mg + 1 Fe2O3  2 Fe + 3 MgO
Type of reaction: single displacement
c)
1 C2H4 + 3 O2  2 CO2 + 2 H2O
Type of reaction: combustion
d)
2 PbSO4  2 PbSO3 + 1 O2
Type of reaction: decomposition
e)
2 SO2 + 1 O2 2 SO3
Type of reaction: synthesis