2.1.2 States of Matter - Practice Problems
Problem 1 - Easy
Topic: States of Matter
Time: 1 minute
Question:
Which state of matter has a definite shape and a definite volume?
A) Solid
B) Liquid
C) Gas
D) Plasma
Correct Answer: A
Explanation:
A solid keeps both its shape and volume because its particles are tightly bound and resist movement.
Why other answers are wrong:
- B: A liquid keeps volume but flows to the container’s shape.
- C: A gas expands to fill the container and is compressible.
- D: Plasma is an ionized gas state, not a fixed-shape state.
EASA Note:
Basic property questions are common at EASA Level 1.
Problem 2 - Medium
Topic: Latent Heat
Time: 2 minutes
Question:
A liquid is changing into vapor in a controlled test (steady pressure). What best describes its temperature during the change?
A) It rises continuously
B) It stays constant during the change
C) It drops rapidly
D) It becomes impossible to measure
Correct Answer: B
Explanation:
During a phase change, added energy can be absorbed as latent heat to change state instead of raising temperature. Temperature rises again after the change completes.
Why other answers are wrong:
- A: Continuous rise is typical after the phase change is complete, not during it.
- C: Temperature does not necessarily drop during boiling in a controlled case.
- D: Temperature is measurable; it can remain constant.
EASA Note:
Look for 'latent heat' and 'temperature constant during phase change' clues.
Problem 3 - Medium
Topic: Boiling Point vs Pressure
Time: 2 minutes
Question:
What happens to a liquid’s boiling point if the pressure on it is reduced?
A) Boiling point increases
B) Boiling point decreases
C) Boiling point stays the same
D) Boiling point becomes unrelated to temperature
Correct Answer: B
Explanation:
Lower pressure makes it easier for a liquid to turn into vapor, so boiling point decreases. Higher pressure raises boiling point.
Why other answers are wrong:
- A: This happens when pressure increases, not decreases.
- C: Boiling point is not fixed; it depends on pressure.
- D: Boiling is still defined by temperature and pressure together.
EASA Note:
EASA commonly links altitude/pressure changes to boiling point behavior.
Problem 4 - Medium
Topic: Compressibility
Time: 2 minutes
Question:
Why do hydraulic systems use liquids rather than gases to transmit force?
A) Liquids are highly compressible
B) Liquids are nearly incompressible
C) Gases have fixed volume
D) Gases hold a fixed shape
Correct Answer: B
Explanation:
Liquids are nearly incompressible, so pressure transmits force efficiently to actuators. Gases compress significantly and behave more like springs.
Why other answers are wrong:
- A: Liquids are not highly compressible; gases are.
- C: Gases do not have fixed volume; they expand to fill containers.
- D: Gases do not have fixed shape; they take the container shape.
EASA Note:
If the question is about force transmission, incompressible liquids are usually the correct concept.
Problem 5 - Hard
Topic: Vapor Pressure and Volatility
Time: 3 minutes
Question:
After a hot turnaround, a Boeing 737 shows symptoms consistent with vapor formation in the fuel system. Which condition most increases vapor formation risk?
A) Low temperature and high pressure
B) Low temperature and low pressure
C) High temperature and low pressure
D) High temperature and high pressure
Correct Answer: C
Explanation:
High temperature increases vapor pressure, and low pressure lowers the boiling point, making vapor formation more likely. Together they increase vapor lock/cavitation risk.
Why other answers are wrong:
- A: Both conditions reduce vapor formation risk.
- B: Low temperature reduces vapor pressure, so vapor formation is less likely.
- D: High pressure tends to suppress boiling and vapor formation.
EASA Note:
Scenario wording like 'hot' + 'low pressure' usually points to vapor pressure/boiling point effects.