9 (a) Which of these means changing state from solid directly to gas?
A condensing
B freezing
C melting
D sublimating
(b) An object has a mass of 7.22 x 10^2 kg and a volume of 2.69 x 10^-3 m^3 - Edexcel - GCSE Physics - Question 9 - 2023 - Paper 2
Question 9
9 (a) Which of these means changing state from solid directly to gas?
A condensing
B freezing
C melting
D sublimating
(b) An object has a mass of 7.22... show full transcript
Worked Solution & Example Answer:9 (a) Which of these means changing state from solid directly to gas?
A condensing
B freezing
C melting
D sublimating
(b) An object has a mass of 7.22 x 10^2 kg and a volume of 2.69 x 10^-3 m^3 - Edexcel - GCSE Physics - Question 9 - 2023 - Paper 2
Step 1
Which of these means changing state from solid directly to gas?
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Answer
The answer is D: sublimating. Sublimation describes the change of state from solid directly to gas, bypassing the liquid phase.
Step 2
Calculate the density, ρ, of the object.
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Answer
To calculate the density, use the formula:
ho = \frac{m}{V}$$
Substituting the given values:
ho = \frac{7.22 \times 10^2 \text{ kg}}{2.69 \times 10^{-3} \text{ m}^3} \approx 2680 \text{ kg/m}^3$$
Thus, the density is approximately 2680 kg/m³.
Step 3
State the unit.
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Answer
The unit of density is kg/m³.
Step 4
Calculate the melting point of aluminium in kelvin.
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Answer
To convert the melting point from Celsius to Kelvin, use the formula: K=°C+273
Substituting the value: K=660+273=933extK
Step 5
Describe the motion of particles in liquid aluminium (above 660°C).
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Answer
In liquid aluminium, the particles have more energy compared to solid aluminium. Therefore, they can move freely in any direction and bump into each other. The motion is random, allowing them to have various speeds and kinetic energies. This results in a fluid state where the particles can slide over each other.
