## Internal Energy

isochoric/isometric: $\Delta V = 0$
isothermal: $\Delta T = 0$
isobaric: $\Delta P = 0$

Hanniel U 2B
Posts: 76
Joined: Fri Sep 28, 2018 12:16 am

### Internal Energy

keyaluo4C
Posts: 54
Joined: Fri Sep 28, 2018 12:17 am

### Re: Internal Energy

$w=-P_{ex}\Delta V$

2. Calculate $\Delta V$
$\Delta V=1.846L-0.345L=1.501L$

3. Convert the given $P_{ex}$ from Torr to atm
$P_{ex}=750 \textup{ torr } \times \frac{1 \textup{ atm}}{760 \textup{ Torr}}=.99\textup{ atm}$

4. Plug into equation for w
$w=-.99 \times 1.5 =-1.49 \textup{L}\cdot \textup{atm}$

5. Convert to kJ

6. Calculate change in internal energy using $\Delta U=q + w$
$\Delta U = 5.35 \textup{\textup{ kJ}}$

Hanniel U 2B
Posts: 76
Joined: Fri Sep 28, 2018 12:16 am

### Re: Internal Energy

$w=-P_{ex}\Delta V$

2. Calculate $\Delta V$
$\Delta V=1.846L-0.345L=1.501L$

3. Convert the given $P_{ex}$ from Torr to atm
$P_{ex}=750 \textup{ torr } \times \frac{1 \textup{ atm}}{760 \textup{ Torr}}=.99\textup{ atm}$

4. Plug into equation for w
$w=-.99 \times 1.5 =-1.49 \textup{L}\cdot \textup{atm}$

5. Convert to kJ

6. Calculate change in internal energy using $\Delta U=q + w$
$\Delta U = 5.35 \textup{\textup{ kJ}}$

Thank You!!!

Matthew ILG 1L
Posts: 112
Joined: Sat Aug 17, 2019 12:15 am

### Re: Internal Energy

I was just on this problem and luckily found this post. Are we supposed to know that 1atm is equivalent to 760 torr or is that somewhere on the equation sheet? Also how do we convert from L*atm to kJ?

Amy Kumar 1I
Posts: 114
Joined: Thu Jul 11, 2019 12:15 am

### Re: Internal Energy

Matthew ILG 1L wrote:I was just on this problem and luckily found this post. Are we supposed to know that 1atm is equivalent to 760 torr or is that somewhere on the equation sheet? Also how do we convert from L*atm to kJ?

Both conversions are given on the constants and equations sheet.
1 L.atm = 101.325 J
1 atm = 760 torr