CHEM 120 – Chamberlain University – 2025/2026 – Introduction to General, Organic & Biological Chemistry Lab Practicum with Verified Questions & Answers

Lab Practicum: CHEM120 / CHEM 120 | New 2025/2026
Update | Introduction to General, Organic & Biological
Chemistry | Questions & Answers | Grade A | 100% Correct
(Verified Solutions) – Chamberlain

Section 1: Introduction
This document contains a set of 100 verified and updated lab practicum questions for
CHEM120 – Introduction to General, Organic, and Biological Chemistry at Chamberlain
University, reflecting the 2025/2026 academic standards.
It includes thoroughly explained answers to questions across key areas such as chemical
bonding, molecular structure, stoichiometry, organic functional groups, acid-base chemistry,
biological macromolecules, and lab safety procedures.
Structured to match the actual lab practicum and graded A+, this guide supports student
mastery of foundational chemistry concepts with 100% verified accuracy.

Section 2: Exam Questions and Answers
Format: Lab-based and conceptual questions with four answer choices (A–D). Correct
answers highlighted. Includes rationale and solution steps aligned with Chamberlain lab
objectives.

Question 1: Chemical Bonding
What type of bond is formed between sodium and chlorine in NaCl?
A) Covalent
B) Ionic
C) Hydrogen
D) Metallic
Correct Answer: B) Ionic
Explanation: Sodium donates an electron to chlorine, forming an ionic bond due to
electrostatic attraction.

Question 2: Chemical Bonding
Which molecule exhibits polar covalent bonding?
A) O₂
B) HCl
C) N₂
D) CH₄
Correct Answer: B) HCl
Explanation: HCl has a polar covalent bond due to the electronegativity difference between
H and Cl.

Question 3: Chemical Bonding
What is the bond angle in a water molecule (H₂O)?
A) 90°
B) 104.5°
C) 120°
D) 180°

,Correct Answer: B) 104.5°
Explanation: Water’s bent geometry, due to lone pairs, results in a bond angle of
approximately 104.5°.

Question 4: Chemical Bonding
Which type of bond is primarily responsible for DNA base pairing?
A) Ionic
B) Covalent
C) Hydrogen
D) Van der Waals
Correct Answer: C) Hydrogen
Explanation: Hydrogen bonds between base pairs stabilize DNA’s double helix.

Question 5: Chemical Bonding
In a lab, you observe a compound with a high melting point and conductivity in solution.
What type of bond is likely?
A) Covalent
B) Ionic
C) Metallic
D) Hydrogen
Correct Answer: B) Ionic
Explanation: High melting point and conductivity in solution indicate ionic bonding.

Question 6: Molecular Structure
What is the molecular geometry of methane (CH₄)?
A) Linear
B) Trigonal planar
C) Tetrahedral
D) Trigonal bipyramidal
Correct Answer: C) Tetrahedral
Explanation: Methane has four bonding pairs, resulting in a tetrahedral geometry.

Question 7: Molecular Structure
What is the hybridization of the carbon atom in CO₂?
A) sp
B) sp²
C) sp³
D) sp³d
Correct Answer: A) sp
Explanation: Carbon in CO₂ forms two double bonds, requiring sp hybridization.

Question 8: Molecular Structure
Which molecule is nonpolar despite having polar bonds?
A) H₂O
B) NH₃
C) CO₂
D) HCl
Correct Answer: C) CO₂
Explanation: CO₂’s linear geometry cancels polar bond dipoles, making it nonpolar.

, Question 9: Molecular Structure
In a lab, you analyze a molecule with a trigonal planar geometry. How many bonding pairs
does the central atom have?
A) 2
B) 3
C) 4
D) 5
Correct Answer: B) 3
Explanation: Trigonal planar geometry requires three bonding pairs, as in BF₃.

Question 10: Molecular Structure
What is the shape of the ammonium ion (NH₄⁺)?
A) Trigonal pyramidal
B) Tetrahedral
C) Bent
D) Linear
Correct Answer: B) Tetrahedral
Explanation: NH₄⁺ has four bonding pairs, resulting in a tetrahedral shape.

Question 11: Stoichiometry
How many moles of NaCl are produced from 2 moles of Na reacting with Cl₂?
A) 1 mole
B) 2 moles
C) 3 moles
D) 4 moles
Correct Answer: B) 2 moles
Explanation: 2Na + Cl₂ → 2NaCl; 2 moles of Na produce 2 moles of NaCl.

Question 12: Stoichiometry
What mass of H₂O is produced from 16 g of O₂ in the reaction 2H₂ + O₂ → 2H₂O?
A) 9 g
B) 18 g
C) 36 g
D) 72 g
Correct Answer: B) 18 g
Explanation: 16 g O₂ = 0.5 mol; 0.5 mol O₂ produces 1 mol H₂O (18 g).

Question 13: Stoichiometry
In a lab, you react 4 g of H₂ with excess O₂. How many moles of H₂O are formed?
A) 1 mole
B) 2 moles
C) 3 moles
D) 4 moles
Correct Answer: B) 2 moles
Explanation: 4 g H₂ = 2 mol; 2H₂ + O₂ → 2H₂O, so 2 mol H₂O.

Question 14: Stoichiometry
What is the limiting reactant when 2 mol of N₂ reacts with 5 mol of H₂ in N₂ + 3H₂ → 2NH₃?
A) N₂
B) H₂