2.1.1 Nature of Matter -Practice problems
Problem 1 - Easy
Topic: Atomic Structure
Time: 1 minute
Question:
Which subatomic particle determines the identity of an element?
A) Neutron
B) Proton
C) Electron
D) Valence shell
Correct Answer: B
Explanation:
The number of protons in the nucleus (atomic number) defines the element. If you change the proton count, you change the element.
Why other answers are wrong:
- A: Neutrons change mass (isotopes) but not the element type.
- C: Electrons affect bonding and conductivity, not the element identity.
- D: The valence shell is a region; it doesn’t define the element.
EASA Note:
Watch for isotope traps: same protons (same element), different neutrons (different mass).
Problem 2 - Medium
Topic: Conservation of Matter
Time: 2 minutes
Question:
During an engine run, a student says the fuel 'disappears' because it turns into exhaust. Which statement is best?
A) Fuel is destroyed when it burns.
B) Fuel becomes energy only; no matter remains.
C) Fuel changes into other substances, mostly gases, so matter is conserved.
D) Fuel turns into a solid residue only.
Correct Answer: C
Explanation:
Combustion converts fuel into other matter (mainly hot gases) while releasing energy. The fuel doesn’t vanish; it changes form.
Why other answers are wrong:
- A: Normal chemical reactions don’t destroy matter.
- B: Energy is released, but matter becomes new substances.
- D: Some residue can form, but most products are gases.
EASA Note:
EASA often tests 'created/destroyed' vs 'changed form/state.' Choose conservation.
Problem 3 - Medium
Topic: Conductors vs Insulators
Time: 2 minutes
Question:
Which option best explains why a metal wire conducts electricity in an aircraft?
A) Its electrons are free to move between atoms.
B) Its valence shell is completely full.
C) Its neutrons are loosely bound and flow.
D) Its nucleus rotates and creates current.
Correct Answer: A
Explanation:
Electrical current is the movement of electrons. In conductors, some electrons can move freely from atom to atom.
Why other answers are wrong:
- B: Full/stable valence shells tend to resist electron movement (insulating behavior).
- C: Neutrons don’t carry charge and don’t ‘flow’ to make current.
- D: Current isn’t created by nucleus rotation in this context.
EASA Note:
Key word 'free electrons' almost always signals conductivity.
Problem 4 - Medium
Topic: Compounds vs Mixtures
Time: 3 minutes
Question:
You find water contamination in aviation fuel. Which is the most accurate statement?
A) Fuel and water form a compound that cannot be separated mechanically.
B) Fuel and water form a mixture and can often be separated by draining/sumping.
C) Water is an element and will evaporate instantly.
D) Water is a plasma inside the fuel tank.
Correct Answer: B
Explanation:
Water and fuel are not chemically bonded; they are physically mixed. Because it’s a mixture, water can often be separated by draining or using fuel system procedures.
Why other answers are wrong:
- A: A compound requires chemical bonding and a fixed ratio; that’s not what’s happening here.
- C: Water is a compound and does not instantly evaporate at tank conditions.
- D: Plasma requires ionization and very high energy, not typical tank conditions.
EASA Note:
EASA likes practical contamination scenarios: identify 'mixture' vs 'compound' correctly.
Problem 5 - Hard
Topic: Isotopes + Identity
Time: 3 minutes
Question:
A component spec references hydrogen-3 (tritium) as radioactive. Which statement is correct about its identity?
A) Hydrogen-3 is a different element because it has a different mass.
B) Hydrogen-3 is the same element as hydrogen-1 because it has the same number of protons.
C) Hydrogen-3 is oxygen because it has more neutrons.
D) Hydrogen-3 is not matter because it is radioactive.
Correct Answer: B
Explanation:
Element identity is set by proton number. Hydrogen-3 has the same proton count as hydrogen-1, but extra neutrons make it a heavier isotope (and it can be radioactive).
Why other answers are wrong:
- A: Different mass alone doesn’t change the element; protons do.
- C: Neutron count doesn’t turn hydrogen into oxygen; proton count does.
- D: Radioactive materials are still matter; they just have unstable nuclei.
EASA Note:
If the question mentions isotopes, lock onto protons for identity and neutrons for mass.