MTTC Physical Science 1 — Questions and Answers
Question 1: Which of the following best describes the law of conservation of mass?
- Mass is created during a chemical reaction
- In a chemical reaction, the total mass of reactants equals the total mass of products (Correct answer)
- Mass disappears when substances are burned
- Mass only applies to solids, not gases
Correct answer: In a chemical reaction, the total mass of reactants equals the total mass of products
The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction.
Question 2: A student observes that iron rusts when exposed to oxygen and water. This is best classified as a:
- Physical change
- Nuclear change
- Chemical change (Correct answer)
- Phase change
Correct answer: Chemical change
Rusting is a chemical change because a new substance (iron oxide) is formed with different properties from the original iron.
Question 3: Which of Newton's laws of motion states that for every action there is an equal and opposite reaction?
- First law
- Second law
- Third law (Correct answer)
- Law of universal gravitation
Correct answer: Third law
Newton's Third Law states that forces always come in equal and opposite pairs between interacting objects.
Question 4: What type of energy is stored in the chemical bonds of food?
- Kinetic energy
- Nuclear energy
- Thermal energy
- Chemical potential energy (Correct answer)
Correct answer: Chemical potential energy
Food stores chemical potential energy in molecular bonds, which is released during cellular respiration.
Question 5: Which best explains why metals are good conductors of electricity?
- Metal atoms are very heavy
- Metals have free electrons that can move easily through the material (Correct answer)
- Metals have tightly bound electrons that resist movement
- Metal atoms are closely packed in a lattice
Correct answer: Metals have free electrons that can move easily through the material
Metals have a 'sea of electrons' that are not bound to individual atoms, allowing electric charge to flow freely.
Question 6: A teacher demonstrates that sound cannot travel through a vacuum by placing a ringing alarm inside a sealed jar and pumping out the air. What concept does this illustrate?
- Sound is a transverse wave
- Light travels at 3×10⁸ m/s
- Sound requires a medium to travel through (Correct answer)
- Sound has a lower frequency than visible light
Correct answer: Sound requires a medium to travel through
Sound is a mechanical wave that requires a medium (solid, liquid, or gas) to propagate; it cannot travel through empty space.
MTTC Physical Science 1
Which of the following best describes the law of conservation of mass?