CHEM 210 EXAMS MODULE 1-8 AND FINAL EXAM
WITH ACTUAL CORRECT QUESTIONS AND
VERIFIED DETAILED ANSWERS |CURRENTLY
TESTING QUESTIONS AND SOLUTIONS|ALREADY
GRADED A+ |JUST RELEASED!!|GUARANTEED
PASS
1. Which of the following is a physical change?
A. Rusting of iron
B. Burning propane
C. Melting ice
D. Digestion of food
Correct Answer: C
Rationale:
A physical change alters state or appearance without changing chemical identity. Melting ice
is still H₂O. Rusting, burning, and digestion involve chemical reactions.
2. How many significant figures are in 0.004560?
A. 2
B. 3
C. 4
D. 5
Correct Answer: C
3. Which particle determines the identity of an element?
A. Electron
B. Neutron
C. Proton
D. Mass number
Correct Answer: C
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,Rationale:
The number of protons (atomic number) defines the element. Changing electrons forms ions;
changing neutrons forms isotopes.
4. Which element has the largest atomic radius?
A. Na
B. Mg
C. Al
D. Cl
Correct Answer: A
Rationale:
Atomic radius decreases left → right across a period due to increasing nuclear charge. Sodium
is farthest left.
5. How many moles are in 36.0 g of water (H₂O)?
A. 1.0 mol
B. 2.0 mol
C. 3.0 mol
D. 4.0 mol
Correct Answer: B
Rationale:
Molar mass of H₂O = 18.0 g/mol
36.0 g ÷ 18.0 g/mol = 2.0 mol
6. Balance the equation:
[__ Al + __ O_2 \rightarrow __ Al_2O_3]
A. 2, 3, 2
B. 4, 3, 2
C. 2, 1, 1
D. 4, 1, 2
Correct Answer: B
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,Rationale:
Balanced equation:
[4Al + 3O_2 \rightarrow 2Al_2O_3]
7. Which gas law explains why a balloon expands when heated?
A. Boyle’s Law
B. Charles’s Law
C. Avogadro’s Law
D. Dalton’s Law
Correct Answer: B
Rationale:
Charles’s Law states that volume is directly proportional to temperature at constant pressure.
8. A gas occupies 2.0 L at 1.0 atm. What is the volume at 2.0 atm (constant temperature)?
A. 1.0 L
B. 2.0 L
C. 3.0 L
D. 4.0 L
Correct Answer: A
Rationale:
Boyle’s Law:
[P_1V_1 = P_2V_2]
[\(1.0)(2.0) = (2.0)(V_2)
\Rightarrow V_2 = 1.0 L]
9. An exothermic reaction:
A. Absorbs heat
B. Releases heat
C. Has ΔH > 0
D. Lowers surroundings’ temperature
Correct Answer: B
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, Rationale:
Exothermic reactions release heat and have negative ΔH.
10. If ΔH = –250 kJ, the reaction is:
A. Endothermic
B. Exothermic
C. At equilibrium
D. Nonspontaneous
Correct Answer: B
Rationale:
Negative enthalpy change = heat released.
11. What type of bond forms between Na and Cl?
A. Covalent
B. Metallic
C. Ionic
D. Hydrogen
Correct Answer: C
Rationale:
Large electronegativity difference → electron transfer → ionic bond.
12. Which molecule is polar?
A. CO₂
B. CH₄
C. H₂O
D. O₂
Correct Answer: C
Rationale:
H₂O has bent geometry and unequal charge distribution → polar.
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WITH ACTUAL CORRECT QUESTIONS AND
VERIFIED DETAILED ANSWERS |CURRENTLY
TESTING QUESTIONS AND SOLUTIONS|ALREADY
GRADED A+ |JUST RELEASED!!|GUARANTEED
PASS
1. Which of the following is a physical change?
A. Rusting of iron
B. Burning propane
C. Melting ice
D. Digestion of food
Correct Answer: C
Rationale:
A physical change alters state or appearance without changing chemical identity. Melting ice
is still H₂O. Rusting, burning, and digestion involve chemical reactions.
2. How many significant figures are in 0.004560?
A. 2
B. 3
C. 4
D. 5
Correct Answer: C
3. Which particle determines the identity of an element?
A. Electron
B. Neutron
C. Proton
D. Mass number
Correct Answer: C
1|Page
,Rationale:
The number of protons (atomic number) defines the element. Changing electrons forms ions;
changing neutrons forms isotopes.
4. Which element has the largest atomic radius?
A. Na
B. Mg
C. Al
D. Cl
Correct Answer: A
Rationale:
Atomic radius decreases left → right across a period due to increasing nuclear charge. Sodium
is farthest left.
5. How many moles are in 36.0 g of water (H₂O)?
A. 1.0 mol
B. 2.0 mol
C. 3.0 mol
D. 4.0 mol
Correct Answer: B
Rationale:
Molar mass of H₂O = 18.0 g/mol
36.0 g ÷ 18.0 g/mol = 2.0 mol
6. Balance the equation:
[__ Al + __ O_2 \rightarrow __ Al_2O_3]
A. 2, 3, 2
B. 4, 3, 2
C. 2, 1, 1
D. 4, 1, 2
Correct Answer: B
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,Rationale:
Balanced equation:
[4Al + 3O_2 \rightarrow 2Al_2O_3]
7. Which gas law explains why a balloon expands when heated?
A. Boyle’s Law
B. Charles’s Law
C. Avogadro’s Law
D. Dalton’s Law
Correct Answer: B
Rationale:
Charles’s Law states that volume is directly proportional to temperature at constant pressure.
8. A gas occupies 2.0 L at 1.0 atm. What is the volume at 2.0 atm (constant temperature)?
A. 1.0 L
B. 2.0 L
C. 3.0 L
D. 4.0 L
Correct Answer: A
Rationale:
Boyle’s Law:
[P_1V_1 = P_2V_2]
[\(1.0)(2.0) = (2.0)(V_2)
\Rightarrow V_2 = 1.0 L]
9. An exothermic reaction:
A. Absorbs heat
B. Releases heat
C. Has ΔH > 0
D. Lowers surroundings’ temperature
Correct Answer: B
3|Page
, Rationale:
Exothermic reactions release heat and have negative ΔH.
10. If ΔH = –250 kJ, the reaction is:
A. Endothermic
B. Exothermic
C. At equilibrium
D. Nonspontaneous
Correct Answer: B
Rationale:
Negative enthalpy change = heat released.
11. What type of bond forms between Na and Cl?
A. Covalent
B. Metallic
C. Ionic
D. Hydrogen
Correct Answer: C
Rationale:
Large electronegativity difference → electron transfer → ionic bond.
12. Which molecule is polar?
A. CO₂
B. CH₄
C. H₂O
D. O₂
Correct Answer: C
Rationale:
H₂O has bent geometry and unequal charge distribution → polar.
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