Question

WHOSE Good with Chemistry to figure this question out?

Calculate the work in joules if the external pressure is 825 torr.
Remeber 1 L atm = 101.3 J

Answer 1

`\large \boxed{\text{220 J}}`

Step-by-step explanation:

1. Convert the pressure to atmospheres

`p = \text{825 Torr} * \frac{\text{1 atm}}{\text{760 Torr}} = \text{1.086 atm}`

2. Calculate the work done

`w = -p\Delta V = -p(V_(f) - V_(i)) = -\text{(1.086 atm)}(\text{2.0 L - 4.0 L})\\\\ = -\text{1.086 atm} * \text{(-2.0 L)} = \text{2.17 L$\cdot$atm}`

3. Convert litre atmospheres to joules

`w = \text{2.17 L$\cdot$atm} * \frac{\text{101.3 J}}{\text{1 L$\cdot$atm}} = \textbf{220 J}\\\\\text{The work done is $\large \boxed{\textbf{220 J}}$}`

Note that the volume is decreasing, so work is being done on the system.