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 m³ - 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... 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 m³ - 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 correct answer is D sublimating. This is because sublimation describes a change of state directly from solid to gas without passing through a liquid phase.
Step 2
Calculate the density, ρ, of the object.
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Answer
To calculate the density, we can use the formula:
ho = \frac{m}{V}$$
Substituting the values:
ho = \frac{7.22 \times 10^2 , \text{kg}}{2.69 \times 10^{-3} , \text{m}^3}$$
By performing the division, we find that:
ho ≈ 2680 \, \text{kg/m}^3$$
Thus, the answer is:
**density = 2680 kg/m³**.
Step 3
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
For aluminium: K=660+273=933K
Thus, the answer is: melting point of aluminium = 933 K.
Step 4
Describe the motion of particles in liquid aluminium (above 660 °C).
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Answer
In liquid aluminium, the particles exhibit the following motion:
The motion is random, meaning that particles move freely in any direction.
They have various speeds and kinetic energies, leading to a wide range of particle velocities.
Particles collide and bump into one another as they move around.
Compared to solid aluminium, liquid particles have much more kinetic energy, allowing them to slide past one another easily.
