IB Physics HL B 3 5 Ideal Gas Equations Questions

Practise IB Physics HL B.3.5 by combining pV=nRT, pV=NkBT and multi-state gas data in demanding calculation problems.

Exam points

Relate work done by the resultant force on a system to the change in its energy.
Apply work–energy reasoning to calculate kinetic or potential energy changes from complete mark-scheme evidence.

[Maximum number: 2]

(a)

An ideal monatomic gas is kept in a container of volume $2.1 \times 10^{-4} \mathrm{~m}^{3}$ , temperature 310 K and pressure $5.3 \times 10^{5} \mathrm{~Pa}$ .

[ 1 ]

(i)

Calculate the number of atoms in the gas.

[ 1 ]

$N=\frac{pV}{kT}=\frac{5.3\times10^{5}\times2.1\times10^{-4}}{1.38\times10^{-23}\times310}=2.6\times10^{22}$

(b)

The volume of the gas in (a) is increased to $6.8 \times 10^{-4} \mathrm{~m}^{3}$ at constant temperature.

[ 1 ]

(i)

Calculate, in Pa , the new pressure of the gas.

[ 1 ]

$p_2=5.3\times10^{5}\times\frac{2.1\times10^{-4}}{6.8\times10^{-4}}=1.6\times10^{5}\ \mathrm{Pa}$

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IB Physics HL B 3 5 Ideal Gas Equations Questions question 1

Question (a)

Question (i)

Question (b)

Question (i)