- #1

TechieDork

- 55

- 22

- Homework Statement:
- -Calculating a Cv from the given equation and data , if everything goes right you'll obtain Cv=26 J*K^-1*mol^-1 as a result.

- Relevant Equations:
- $$C_{V}=\frac{p_{0} V_{0}}{T_{0}} \cdot\left(\frac{U \cdot I \Delta t}{(a p+V) \cdot \Delta p}-\frac{a p}{a p+V}\right)$$

I've conducted this experiment yesterday. The main goal of this experiment is to find a gas constant R and compare it with its theoretical counterpart but I get stuck in calculating a Cv so I tried to find out what's wrong with my calculations by trying to calculate a Cv from the given data.

...(1)

where p0 = 1013 hPa , T0=273.2 K , V0 = 22414 ml/mol

U = 4.75 V , I = 0.25 A

a = 0.855 cm^3/hPa

p = 0.147 hPa

V = 1.14 L = 1140 mL

delta(p)/delta(t) = 1.67 hPa/s or delta(t)/delta(t) = 0.5988 s/hPa

If everything goes right I'll obtain Cv = 26 J*K-1*mol^-1 as a result

My attempt :

...(2)

...(3)

Plugged all the given values into the eq(2) and I got 42.67 instead of 26.

Here this is the documentation : https://www.nikhef.nl/~h73/kn1c/praktikum/phywe/LEP/Experim/3_2_02.pdf (page 4 and 5)

where p0 = 1013 hPa , T0=273.2 K , V0 = 22414 ml/mol

U = 4.75 V , I = 0.25 A

a = 0.855 cm^3/hPa

p = 0.147 hPa

V = 1.14 L = 1140 mL

delta(p)/delta(t) = 1.67 hPa/s or delta(t)/delta(t) = 0.5988 s/hPa

If everything goes right I'll obtain Cv = 26 J*K-1*mol^-1 as a result

My attempt :

Plugged all the given values into the eq(2) and I got 42.67 instead of 26.

**What is wrong with my calculation?**, could someone please shed some light on this?Here this is the documentation : https://www.nikhef.nl/~h73/kn1c/praktikum/phywe/LEP/Experim/3_2_02.pdf (page 4 and 5)

#### Attachments

Last edited: