GACE Chemistry 4 — Questions and Answers
Question 1: In a galvanic (voltaic) cell, which electrode undergoes oxidation?
- Cathode
- Both electrodes equally
- Anode (Correct answer)
- The salt bridge
Correct answer: Anode
Oxidation (loss of electrons) always occurs at the anode in both galvanic and electrolytic cells.
Question 2: What is the VSEPR geometry of a molecule with 4 bonding pairs and 0 lone pairs around the central atom?
- Trigonal planar
- Bent
- Tetrahedral (Correct answer)
- Linear
Correct answer: Tetrahedral
Four bonding pairs with no lone pairs arrange themselves into a tetrahedral geometry to minimize repulsion.
Question 3: Which colligative property explains why roads are salted in winter to prevent ice formation?
- Boiling point elevation
- Vapor pressure lowering
- Osmotic pressure
- Freezing point depression (Correct answer)
Correct answer: Freezing point depression
Salt dissolves in water and lowers its freezing point, preventing ice from forming at temperatures that would otherwise freeze pure water.
Question 4: Which of the following describes the process of nuclear fission?
- Two light nuclei combine to form a heavier nucleus
- A heavy nucleus splits into smaller nuclei and releases energy (Correct answer)
- An electron is emitted from an unstable nucleus
- A proton is converted to a neutron in the nucleus
Correct answer: A heavy nucleus splits into smaller nuclei and releases energy
In nuclear fission, a heavy nucleus such as uranium-235 splits into smaller fragments, releasing a large amount of energy.
Question 5: Which intermolecular force is responsible for the unusually high boiling point of water compared to other small molecules like H₂S?
- London dispersion forces
- Dipole-dipole forces
- Hydrogen bonding (Correct answer)
- Ionic interactions
Correct answer: Hydrogen bonding
Water molecules form strong hydrogen bonds with each other due to the highly electronegative oxygen atom bonded to hydrogen.
Question 6: A chemist performs a titration and finds that 25.0 mL of 0.40 M NaOH neutralizes an unknown acid. How many millimoles of acid were present, assuming 1:1 stoichiometry?
- 5 mmol
- 10 mmol (Correct answer)
- 15 mmol
- 20 mmol
Correct answer: 10 mmol
Millimoles of NaOH = 25.0 mL × 0.40 mmol/mL = 10.0 mmol; at 1:1 stoichiometry, moles of acid = 10 mmol.
Question 7: What is the primary purpose of a control group in a chemistry experiment?
- To increase the number of trials
- To provide a baseline for comparison with the experimental group (Correct answer)
- To identify the independent variable
- To eliminate all sources of error
Correct answer: To provide a baseline for comparison with the experimental group
The control group is kept under standard conditions so that results from the experimental group can be compared against it to determine the effect of the variable.
GACE Chemistry 4
In a galvanic (voltaic) cell, which electrode undergoes oxidation?