CIE iGCSE Co-Ordinated Science C1.2 Diffusion Exam Style Questions Paper 2
▶️ Answer/Explanation
The rate of diffusion is inversely proportional to the square root of the molar mass. Ammonia (NH₃) has the smallest molar mass (17 g/mol) compared to butane (58), CO₂ (44), and Cl₂ (71). Hence, ammonia diffuses fastest.
✅ Answer: (A)
✅ Answer: (A)
▶️ Answer/Explanation
\(P_4O_{10}\) contains \(4\) phosphorus atoms and \(10\) oxygen atoms chemically combined in a fixed ratio, making it a compound.
Since it contains more than one atom bonded together, it represents a single molecule of that compound, not just an atom or a mixture.
✅ Answer: (C)
Since it contains more than one atom bonded together, it represents a single molecule of that compound, not just an atom or a mixture.
✅ Answer: (C)
▶️ Answer/Explanation
A chemical change produces one or more new substances, whereas a physical change does not.
Burning methane produces carbon dioxide and water, and rusting iron produces iron oxide, so both are chemical changes.
Dissolving sugar and evaporating ethanol are both physical changes, since no new substance is formed and the process is reversible.
✅ Answer: (B)
Burning methane produces carbon dioxide and water, and rusting iron produces iron oxide, so both are chemical changes.
Dissolving sugar and evaporating ethanol are both physical changes, since no new substance is formed and the process is reversible.
✅ Answer: (B)
▶️ Answer/Explanation
Hydrogen has a lower molecular mass (2) than fluorine (38). According to kinetic theory, lighter gas particles move faster at the same temperature, so hydrogen diffuses faster. The reason is its lower molecular mass.
✅ Answer: (C)
✅ Answer: (C)