How in the bomb calorimeter the water is recondensed?

Elz
Messages
12
Reaction score
0
1. In the bomb calorimeter used for the test the water is recondensed after it is vaporized

In the bomb calorimeter we measure the HHV as the steam formed there is condensed. What I want to know is how the steam is re condensed? In the wikipedia it says In more recent calorimeter designs, the whole bomb, pressurized with excess pure oxygen (typically at 30atm) and containing a weighed mass of a sample (typically 1-1.5 g) and a small fixed amount of water (to saturate the internal atmosphere, thus ensuring that all water produced is liquid, and removing the need to include enthalpy of vaporization in calculations), is submerged under a known volume of water
...
http://en.wikipedia.org/wiki/Calorimeter#Bomb_calorimeters

If a small amount of water is admitted into the bomb then how it is condensing the steam? Also Bomb calorimeter is called a constant volume calorimeter, What does this constant volume mean? As the bomb calorimeter has to withstand high pressure so what does this constant volume refer to?

Please help me with this.
 
Physics news on Phys.org
Any additional steam would increase the humidity above 100%, therefore it condenses (unless the temperature increases significantly).
What does this constant volume mean?
What is unclear about constant volume? The whole setup has a fixed volume, it cannot expand or emit any stuff.
As the bomb calorimeter has to withstand high pressure
That is a side-effect of the constant volume: The pressure can be high.
 
mfb said:
Any additional steam would increase the humidity above 100%, therefore it condenses (unless the temperature increases significantly).

Additional steam?
I also found in a report that introducing pure oxygen to the bomb would increase the pressure in an isochoric chamber, thus ensuring that the water would be liquid. Can you please explain how it works? I mean i just want to be clear about the mechanism.

What is unclear about constant volume?

Why it is done in constant volume?

Thanks for you response.
 
I also found in a report that introducing pure oxygen to the bomb would increase the pressure in an isochoric chamber, thus ensuring that the water would be liquid. Can you please explain how it works? I mean i just want to be clear about the mechanism.
A high pressure increases the boiling point.
Why it is done in constant volume?
The scientist wanted to study something at constant volume, I think. Why? That depends on the experiment.
 
Well, it is a bomb calorimeter.

If the reaction didn't occur at constant volume, that would imply that the bomb spread itself all over the lab.
 
Thread 'Need help understanding this figure on energy levels'
This figure is from "Introduction to Quantum Mechanics" by Griffiths (3rd edition). It is available to download. It is from page 142. I am hoping the usual people on this site will give me a hand understanding what is going on in the figure. After the equation (4.50) it says "It is customary to introduce the principal quantum number, ##n##, which simply orders the allowed energies, starting with 1 for the ground state. (see the figure)" I still don't understand the figure :( Here is...
Thread 'Understanding how to "tack on" the time wiggle factor'
The last problem I posted on QM made it into advanced homework help, that is why I am putting it here. I am sorry for any hassle imposed on the moderators by myself. Part (a) is quite easy. We get $$\sigma_1 = 2\lambda, \mathbf{v}_1 = \begin{pmatrix} 0 \\ 0 \\ 1 \end{pmatrix} \sigma_2 = \lambda, \mathbf{v}_2 = \begin{pmatrix} 1/\sqrt{2} \\ 1/\sqrt{2} \\ 0 \end{pmatrix} \sigma_3 = -\lambda, \mathbf{v}_3 = \begin{pmatrix} 1/\sqrt{2} \\ -1/\sqrt{2} \\ 0 \end{pmatrix} $$ There are two ways...
Back
Top