ASVAB General Science: Physics and Chemistry Concepts 5 — Questions and Answers
Question 1: What is the term for the minimum energy required to start a chemical reaction?
- Kinetic energy
- Activation energy (Correct answer)
- Potential energy
- Chemical energy
Correct answer: Activation energy
Activation energy is the minimum energy needed to initiate a chemical reaction by breaking existing bonds.
Question 2: Which phenomenon explains why a straw appears bent when placed in a glass of water?
- Reflection
- Diffraction
- Refraction (Correct answer)
- Dispersion
Correct answer: Refraction
Refraction occurs when light changes speed as it passes from one medium (air) to another (water), bending the apparent position of objects.
Question 3: What is the correct representation of water's chemical formula?
- HO
- H₂O₂
- H₂O (Correct answer)
- OH₂
Correct answer: H₂O
Water consists of two hydrogen atoms covalently bonded to one oxygen atom, giving the formula H₂O.
Question 4: According to Charles's Law, what happens to the volume of a gas when temperature increases at constant pressure?
- Volume decreases
- Volume stays the same
- Volume increases (Correct answer)
- Volume becomes zero
Correct answer: Volume increases
Charles's Law states that volume and temperature are directly proportional at constant pressure, so higher temperature means greater volume.
Question 5: Which of the following is NOT a form of potential energy?
- Gravitational potential energy
- Elastic potential energy
- Chemical potential energy
- Kinetic energy of a moving car (Correct answer)
Correct answer: Kinetic energy of a moving car
Kinetic energy is the energy of motion, not stored (potential) energy; the other choices are all forms of stored energy.
Question 6: What is the term for a substance that speeds up a chemical reaction without being consumed?
- Reactant
- Product
- Catalyst (Correct answer)
- Solvent
Correct answer: Catalyst
A catalyst lowers the activation energy of a reaction and is not consumed in the process, allowing it to be reused.
Question 7: Which property of a wave determines its pitch when heard as sound?
- Amplitude
- Wavelength
- Speed
- Frequency (Correct answer)
Correct answer: Frequency
The pitch of a sound is determined by its frequency; higher frequency waves produce higher-pitched sounds.
ASVAB General Science: Physics and Chemistry Concepts 5
What is the term for the minimum energy required to start a chemical reaction?