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The average mass of an air molecule is 4.8 × 10^-26 kg - AQA - A-Level Physics - Question 10 - 2018 - Paper 2
Question 10
The average mass of an air molecule is 4.8 × 10^-26 kg. What is the mean square speed of an air molecule at 750 K?
Worked Solution & Example Answer:The average mass of an air molecule is 4.8 × 10^-26 kg - AQA - A-Level Physics - Question 10 - 2018 - Paper 2
Step 1
Calculate the mean square speed using the formula
Answer
The mean square speed of a gas molecule can be calculated using the formula:
v_{rms} = rac{3kT}{m}
Where:
- is the root mean square speed,
- is the Boltzmann constant (),
- is the temperature in Kelvin,
- is the mass of a molecule in kilograms.
For this problem:
- ,
- .
Plugging in the values, we calculate:
v_{rms} = rac{3 imes (1.38 × 10^{-23}) imes 750}{4.8 × 10^{-26}}
Step 2