At a constant temperature, the volume of a gas is inversely proportional to its pressure.

Some gas has a pressure of [tex]$1.8 \times 10^6$[/tex] Pascals and a volume of [tex]$2.1 \times 10^{-8} \, m^3$[/tex].

a) What will the volume of the gas be when its pressure is [tex][tex]$4.1 \times 10^4$[/tex][/tex] Pascals?

b) Work out the pressure of the gas when its volume is [tex]$7.1 \times 10^{-9} \, m^3$[/tex].

Give each of your answers in standard form to 3 significant figures (s.f.).



Answer :

Let's solve the problem step by step:

### Part (a)

Given:
- Initial pressure, [tex]\( P_1 = 1.8 \times 10^6 \)[/tex] Pascals
- Initial volume, [tex]\( V_1 = 2.1 \times 10^{-8} \)[/tex] m³
- New pressure, [tex]\( P_2 = 4.1 \times 10^4 \)[/tex] Pascals

We need to find the new volume, [tex]\( V_2 \)[/tex].

According to Boyle's Law, at constant temperature, the pressure and volume of a gas are inversely proportional:
[tex]\[ P_1 V_1 = P_2 V_2 \][/tex]

Substituting the given values into the equation:
[tex]\[ (1.8 \times 10^6) \times (2.1 \times 10^{-8}) = (4.1 \times 10^4) \times V_2 \][/tex]

[tex]\[ 3.78 \times 10^{-2} = (4.1 \times 10^4) \times V_2 \][/tex]

Solving for [tex]\( V_2 \)[/tex]:
[tex]\[ V_2 = \frac{3.78 \times 10^{-2}}{4.1 \times 10^4} \][/tex]

[tex]\[ V_2 = \frac{3.78}{4.1} \times 10^{-2 - 4} \][/tex]

[tex]\[ V_2 = 0.92195 \times 10^{-6} \][/tex]

Converting the result to standard form to 3 significant figures:
[tex]\[ V_2 \approx 9.220 \times 10^{-7} \, \text{m}^3 \][/tex]

### Part (b)

Given:
- Initial pressure, [tex]\( P_1 = 1.8 \times 10^6 \)[/tex] Pascals
- Initial volume, [tex]\( V_1 = 2.1 \times 10^{-8} \)[/tex] m³
- New volume, [tex]\( V_2 = 7.1 \times 10^{-9} \)[/tex] m³

We need to find the new pressure, [tex]\( P_2 \)[/tex].

According to Boyle's Law, at constant temperature, the pressure and volume of a gas are inversely proportional:
[tex]\[ P_1 V_1 = P_2 V_2 \][/tex]

Substituting the given values into the equation:
[tex]\[ (1.8 \times 10^6) \times (2.1 \times 10^{-8}) = P_2 \times (7.1 \times 10^{-9}) \][/tex]

[tex]\[ 3.78 \times 10^{-2} = P_2 \times (7.1 \times 10^{-9}) \][/tex]

Solving for [tex]\( P_2 \)[/tex]:
[tex]\[ P_2 = \frac{3.78 \times 10^{-2}}{7.1 \times 10^{-9}} \][/tex]

[tex]\[ P_2 = \frac{3.78}{7.1} \times 10^{-2 + 9} \][/tex]

[tex]\[ P_2 = 0.53239 \times 10^{7} \][/tex]

Converting the result to standard form to 3 significant figures:
[tex]\[ P_2 \approx 5.324 \times 10^{6} \, \text{Pascals} \][/tex]

So, the final answers are:
a) The volume of the gas will be [tex]\( 9.220 \times 10^{-7} \)[/tex] m³.
b) The pressure of the gas will be [tex]\( 5.324 \times 10^6 \)[/tex] Pascals.

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