CHEM 120 WEEK 1 TO WEEK 17 PRACTICE QUESTIONS AND
ANSWERS (MORE THAN 170 Q/A)
1. Question No. : (TCO 2) The atomic number of an atom is equal to the number of
Student Ans:
electrons plus protons.
nuclei.
neutrons plus protons.
protons.
neutrons.
Inst. Exp: Chapter 3; The atomic number = number of protons
1921547766 MultipleChoice 2 True
0 1921547766 MultipleChoice 2
2. Question No. : (TCO 2) Consider a neutral atom with 30 protons & 34 neutrons. The
atomic number of the element is
Student Ans:
94.
30.
64.
32.
34.
Inst. Exp: Chapter 3; Atomic number = number of protons. Therefore, in this case, the atomic
number = 30.
1921547767 MultipleChoice 5
0 1921547767 MultipleChoice 5
3. Question No. : (TCO 2) No matter how much extra oxygen is available, 12 grams of
carbon always combines with 32 grams of oxygen. This best illustrates
the law of
Student Ans:
conservation of mass.
, multiple proportions.
definite proportions.
All of the above
None of the above
Inst. Exp: Chapter 2
MultipleChoice 8 False
1921547768 8
4. Question No. : (TCO 2) Which type of radioactivity has a negative charge?
Student Ans:
Alpha
Beta
Gamma
All of the above
None of the above
Inst. Exp: Chapter 3
1921547769 MultipleChoice 11 True
0 1921547769 MultipleChoice 11
5. Question No. : (TCO 2) The proton has
Student Ans:
the same mass & charge as the electron.
a smaller mass & the same charge as the electron.
a smaller mass & opposite charge as the electron.
a larger mass & opposite charge as the electron.
None of the above
Inst. Exp: Chapter 3
1921547770 MultipleChoice 18 True
0 1921547770 MultipleChoice 18
6. Question No. : (TCO 2) Isotopes are atoms of the same element with
, a different number of electrons.
a different number of protons.
different atomic numbers.
None of the above
Inst. Exp: Chapter 3
1921547771 MultipleChoice 22 False
0 1921547771 MultipleChoice 22
7. Question No. : (TCO 2) The atomic number of an element is
Student Ans:
the number of protons in an atom.
equal to the positive charge of an atom’s nucleus.
equal to the number of electrons in a neutral atom.
All of the above are valid definitions.
None of the above
Inst. Exp: Chapter 3
1921547772 MultipleChoice 21 False
0 1921547772 MultipleChoice 21
8. Question No. : (TCO 1) How many meters are in 7 yards? Show your work.
Student Ans: x meters = 7 yd x (0.914 m/1 yd) = 6.4 m
Inst. Exp: x meters = 7 yd x (0.914 m/1 yd) = 6.4 m (Chapter 1; 1 point for units, 1 point
for conversion factor, 1 point for answer)
1921547773 Short 3 False
0 1921547773 Short 3
9. Question No. : (TCO 1) How many quarts are in 12.5 liters? Show your work.
Student Ans: x qts = 12.5 L x (1 qt/0.946 L) = 13.2 L
Inst. Exp: x qts = 12.5 L x (1 qt/0.946 L) = 13.2 L (Chapter 1; 1 point for units, 1 point for
conversion factor, 1 point for answer)
1921547774 Short 8 False
0 1921547774 Short 8
10. Question No. : (TCO 1) What is the mass of 53 mL of ethyl alcohol, which has a
, Student Ans: x g = 53 mL x (0.79 g/mL) = 42 g
Inst. Exp: x g = 53 mL x (0.79 g/mL) = 42 g (Chapter 1; 1 point for units, 1 point for
conversion factor, 1 point for answer)
1921547775 Short 10 False
0 1921547775 Short 10
11. Question No. : (TCO 1) What is the mass of 74 mL of ethyl alcohol, which has a
density of 0.79 g/mL? Show your work.
Student Ans: x g = 74 mL x (0.79 g/mL) = 58.5 g
Inst. Exp: x g = 74 mL x (0.79 g/mL) = 58.5 g (Chapter 1; 1 point for units, 1 point for
conversion factor, 1 point for answer)
1921547777 Short 14 False
0 1921547777 Short 14
12. Question No. : (TCO 2) Determine the number of protons, neutrons, & electron for the
element shown below. The mass number for the isotope of this element
is 90. You must show your work for each determination to receive credit
(2 points per determination).
40
Zr
91.22
Student Ans: Atomic # 40
Protons 40
Electron 40
Electron mass number 90- 40 protons = 50 electrons
Inst. Exp: Chapter 3; The atomic number from the periodic table of elements = 40.
Therefore, the # of protons = 40 (2 points). The # of protons = number of electron;
thus = 40 electrons (2 points). If the mass number is 90, then there are 50
neutrons (# neutrons = mass number - # protons).
1921547779 Short 18 False
0 1921547779 Short 18
13. Question No. : (TCO 1) You have been growing the same variety of corn for over 5
years. In the past two years, you have noticed that the yield has
decreased by 10% each year. You grow corn on 10 acres of l&, & your
yield should be 1,000 bushels per acre. Growing conditions have been
consistent for the past 5 years. You want to identify another variety of
corn that will produce 1,000 bushels per acre. You currently grow
Variety ZQB. You want to test two new varieties, CAQ & TWX. You
hypothesize that CAQ will produce 1,000 bushels per acre. Design an
experiment to test this hypothesis. Include your control(s) (2 points) &
your experimental design (4 points). Describe the experimental results
that would support your hypothesis (2 points). Be specific.
You have been growing tomatoes for a number of years. However, you have not
ANSWERS (MORE THAN 170 Q/A)
1. Question No. : (TCO 2) The atomic number of an atom is equal to the number of
Student Ans:
electrons plus protons.
nuclei.
neutrons plus protons.
protons.
neutrons.
Inst. Exp: Chapter 3; The atomic number = number of protons
1921547766 MultipleChoice 2 True
0 1921547766 MultipleChoice 2
2. Question No. : (TCO 2) Consider a neutral atom with 30 protons & 34 neutrons. The
atomic number of the element is
Student Ans:
94.
30.
64.
32.
34.
Inst. Exp: Chapter 3; Atomic number = number of protons. Therefore, in this case, the atomic
number = 30.
1921547767 MultipleChoice 5
0 1921547767 MultipleChoice 5
3. Question No. : (TCO 2) No matter how much extra oxygen is available, 12 grams of
carbon always combines with 32 grams of oxygen. This best illustrates
the law of
Student Ans:
conservation of mass.
, multiple proportions.
definite proportions.
All of the above
None of the above
Inst. Exp: Chapter 2
MultipleChoice 8 False
1921547768 8
4. Question No. : (TCO 2) Which type of radioactivity has a negative charge?
Student Ans:
Alpha
Beta
Gamma
All of the above
None of the above
Inst. Exp: Chapter 3
1921547769 MultipleChoice 11 True
0 1921547769 MultipleChoice 11
5. Question No. : (TCO 2) The proton has
Student Ans:
the same mass & charge as the electron.
a smaller mass & the same charge as the electron.
a smaller mass & opposite charge as the electron.
a larger mass & opposite charge as the electron.
None of the above
Inst. Exp: Chapter 3
1921547770 MultipleChoice 18 True
0 1921547770 MultipleChoice 18
6. Question No. : (TCO 2) Isotopes are atoms of the same element with
, a different number of electrons.
a different number of protons.
different atomic numbers.
None of the above
Inst. Exp: Chapter 3
1921547771 MultipleChoice 22 False
0 1921547771 MultipleChoice 22
7. Question No. : (TCO 2) The atomic number of an element is
Student Ans:
the number of protons in an atom.
equal to the positive charge of an atom’s nucleus.
equal to the number of electrons in a neutral atom.
All of the above are valid definitions.
None of the above
Inst. Exp: Chapter 3
1921547772 MultipleChoice 21 False
0 1921547772 MultipleChoice 21
8. Question No. : (TCO 1) How many meters are in 7 yards? Show your work.
Student Ans: x meters = 7 yd x (0.914 m/1 yd) = 6.4 m
Inst. Exp: x meters = 7 yd x (0.914 m/1 yd) = 6.4 m (Chapter 1; 1 point for units, 1 point
for conversion factor, 1 point for answer)
1921547773 Short 3 False
0 1921547773 Short 3
9. Question No. : (TCO 1) How many quarts are in 12.5 liters? Show your work.
Student Ans: x qts = 12.5 L x (1 qt/0.946 L) = 13.2 L
Inst. Exp: x qts = 12.5 L x (1 qt/0.946 L) = 13.2 L (Chapter 1; 1 point for units, 1 point for
conversion factor, 1 point for answer)
1921547774 Short 8 False
0 1921547774 Short 8
10. Question No. : (TCO 1) What is the mass of 53 mL of ethyl alcohol, which has a
, Student Ans: x g = 53 mL x (0.79 g/mL) = 42 g
Inst. Exp: x g = 53 mL x (0.79 g/mL) = 42 g (Chapter 1; 1 point for units, 1 point for
conversion factor, 1 point for answer)
1921547775 Short 10 False
0 1921547775 Short 10
11. Question No. : (TCO 1) What is the mass of 74 mL of ethyl alcohol, which has a
density of 0.79 g/mL? Show your work.
Student Ans: x g = 74 mL x (0.79 g/mL) = 58.5 g
Inst. Exp: x g = 74 mL x (0.79 g/mL) = 58.5 g (Chapter 1; 1 point for units, 1 point for
conversion factor, 1 point for answer)
1921547777 Short 14 False
0 1921547777 Short 14
12. Question No. : (TCO 2) Determine the number of protons, neutrons, & electron for the
element shown below. The mass number for the isotope of this element
is 90. You must show your work for each determination to receive credit
(2 points per determination).
40
Zr
91.22
Student Ans: Atomic # 40
Protons 40
Electron 40
Electron mass number 90- 40 protons = 50 electrons
Inst. Exp: Chapter 3; The atomic number from the periodic table of elements = 40.
Therefore, the # of protons = 40 (2 points). The # of protons = number of electron;
thus = 40 electrons (2 points). If the mass number is 90, then there are 50
neutrons (# neutrons = mass number - # protons).
1921547779 Short 18 False
0 1921547779 Short 18
13. Question No. : (TCO 1) You have been growing the same variety of corn for over 5
years. In the past two years, you have noticed that the yield has
decreased by 10% each year. You grow corn on 10 acres of l&, & your
yield should be 1,000 bushels per acre. Growing conditions have been
consistent for the past 5 years. You want to identify another variety of
corn that will produce 1,000 bushels per acre. You currently grow
Variety ZQB. You want to test two new varieties, CAQ & TWX. You
hypothesize that CAQ will produce 1,000 bushels per acre. Design an
experiment to test this hypothesis. Include your control(s) (2 points) &
your experimental design (4 points). Describe the experimental results
that would support your hypothesis (2 points). Be specific.
You have been growing tomatoes for a number of years. However, you have not
