CHEM 280 MIDTERM EXAM REVIEW QUESTIONS AND 100% CORRECT ANSWERS
2026/27 LATEST - WCU
1. A hypothesis can never be proven as wrong
a. True
b. False
2. Where can you find chemicals?
a. In a grocery store
b. Inside the house
c. On the backyard
d. All of the above
3. The distance between the two hydrogen atoms in a molecule of water is 0.000000000172
m. Express this distance in scientific notation.
A) 1.72 ×10-9 m
B) 1.72 × 10-10 m
C) 0.172 × 10-10 m
D) 17.2 × 109 m
E) 1.72 × 1010 m
4. The correct decimal representation of 1.201 × 10-7 is:
A) 12010000
B) 0.0001201
C) 0.0000001201
D) 1201.000
5. Determine the answer for the equation below with correct number of significant figures:
1.2 × 1.79 =
A) 2.148
B) 2.15
C) 2.1
D) 2.2
6. Determine the answer to the following equation with correct number of significant
figures: 13.96 - 4.9102 + 71.5 =
a. 80.5498
b. 81
c. 80.5
d. 80.55
7. The correct prefix for the multiplier 0.000000001 is:
a. mega
b. milli
c. micro
d. nano
CHEM 280 MIDTERM EXAM
, 8. Which state of matter has indefinite shape and is compressible?
a. liquid
b. solid
c. gas
d. plasma
9. A pure substance is:
a. composed of two or more different types of atoms or molecules combined in
variable proportions.
b. composed of only one type of atom or molecule.
c. composed of two or more regions with different compositions.
d. composed of two or more different types of atoms or molecules that has constant
composition.
10. Group 1A elements are also called:
a. noble gases.
b. halogens.
c. alkaline earth metals.
d. alkali metals.
11. When an atom loses an electron, the resulting particle is called
a. a proton.
b. an anion.
c. a cation.
d. an isotope.
12. How many neutrons are present in Carbon-14?
a. 14
b. 12
c. 6
d. 8
13. What is the formula for an ionic compound made of barium and nitrogen?
a. Ba3N2
b. Ba2N3
c. BaN
d. Ba2N4
14. What is the correct formula for the hypochlorite polyatomic ion?
a. ClO-
b. ClO2-
c. ClO3-
d. ClO4-
CHEM 280 MIDTERM EXAM
2026/27 LATEST - WCU
1. A hypothesis can never be proven as wrong
a. True
b. False
2. Where can you find chemicals?
a. In a grocery store
b. Inside the house
c. On the backyard
d. All of the above
3. The distance between the two hydrogen atoms in a molecule of water is 0.000000000172
m. Express this distance in scientific notation.
A) 1.72 ×10-9 m
B) 1.72 × 10-10 m
C) 0.172 × 10-10 m
D) 17.2 × 109 m
E) 1.72 × 1010 m
4. The correct decimal representation of 1.201 × 10-7 is:
A) 12010000
B) 0.0001201
C) 0.0000001201
D) 1201.000
5. Determine the answer for the equation below with correct number of significant figures:
1.2 × 1.79 =
A) 2.148
B) 2.15
C) 2.1
D) 2.2
6. Determine the answer to the following equation with correct number of significant
figures: 13.96 - 4.9102 + 71.5 =
a. 80.5498
b. 81
c. 80.5
d. 80.55
7. The correct prefix for the multiplier 0.000000001 is:
a. mega
b. milli
c. micro
d. nano
CHEM 280 MIDTERM EXAM
, 8. Which state of matter has indefinite shape and is compressible?
a. liquid
b. solid
c. gas
d. plasma
9. A pure substance is:
a. composed of two or more different types of atoms or molecules combined in
variable proportions.
b. composed of only one type of atom or molecule.
c. composed of two or more regions with different compositions.
d. composed of two or more different types of atoms or molecules that has constant
composition.
10. Group 1A elements are also called:
a. noble gases.
b. halogens.
c. alkaline earth metals.
d. alkali metals.
11. When an atom loses an electron, the resulting particle is called
a. a proton.
b. an anion.
c. a cation.
d. an isotope.
12. How many neutrons are present in Carbon-14?
a. 14
b. 12
c. 6
d. 8
13. What is the formula for an ionic compound made of barium and nitrogen?
a. Ba3N2
b. Ba2N3
c. BaN
d. Ba2N4
14. What is the correct formula for the hypochlorite polyatomic ion?
a. ClO-
b. ClO2-
c. ClO3-
d. ClO4-
CHEM 280 MIDTERM EXAM
