Gas Laws & Kinetic Theory — A/L Physics

How do I practise Gas Laws & Kinetic Theory?

1 question with a worked solution

1. According to the kinetic theory of an ideal gas, if the absolute temperature of an ideal gas is increased fourfold from 300 K to 1200 K, by what factor does the root-mean-square (rms) speed of its molecules increase?
   1. A) 16 times
   2. B) 2 times
   3. C) 4 times
   4. D) √2 times
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   Correct answer: B) 2 times

   The root-mean-square speed of ideal gas molecules is given by c_rms = √(3RT / M). Since c_rms is proportional to √T: c_new / c_old = √(T_new / T_old) = √(1200 / 300) = √4 = 2.

   Show worked solution

   Step 1: Formula: c_rms = √(3RT / M) => c_rms ∝ √T. Step 2: c₂ / c₁ = √(T₂ / T₁) = √(1200 / 300) = √4 = 2. Answer: 2 times.
   Modelled on: the A/L Physics examination pattern

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Where does Gas Laws & Kinetic Theory fit in the syllabus?

Unit 4.3 · Year 1 · Term 2