How Can You Identify the Contents of Unlabeled Gas Cylinders Using Basic Tools?

[soccerkid830]

Hello, I have been given the following problem and am hoping for some help...

You have 1000 unlabeled gas cylinders, each are 0.25m3 and need to be able to identify the contents. They mostly contain oxygen and helium, but some contain xenon and uranium hexafluoride. You are given a scale, pressure gauge, unlimited water, bubble gum, duct tape, ice, firewood and matches. You are also given a "fugacity meter" and use of a thermodynamics textbook..

So, using just those items, how can you determine what the cylinders contain?

For bonus points, any use of the Maxwell relations are to be used.

So, if anyone's got any ideas, please help me out :)

 

[berkeman]

Hello, I have been given the following problem and am hoping for some help...

You have 1000 unlabeled gas cylinders, each are 0.25m3 and need to be able to identify the contents. They mostly contain oxygen and helium, but some contain xenon and uranium hexafluoride. You are given a scale, pressure gauge, unlimited water, bubble gum, duct tape, ice, firewood and matches. You are also given a "fugacity meter" and use of a thermodynamics textbook..

So, using just those items, how can you determine what the cylinders contain?

For bonus points, any use of the Maxwell relations are to be used.

So, if anyone's got any ideas, please help me out :)

Yoiks. It seems the scale is the most practical device...?

 

[berkeman]

Hello, I have been given the following problem and am hoping for some help...

You have 1000 unlabeled gas cylinders, each are 0.25m3 and need to be able to identify the contents. They mostly contain oxygen and helium, but some contain xenon and uranium hexafluoride. You are given a scale, pressure gauge, unlimited water, bubble gum, duct tape, ice, firewood and matches. You are also given a "fugacity meter" and use of a thermodynamics textbook..

So, using just those items, how can you determine what the cylinders contain?

For bonus points, any use of the Maxwell relations are to be used.

So, if anyone's got any ideas, please help me out :)

Do you have any ideas?

 

[soccerkid830]

I was thinking something along the lines of placing all the cylinders in the water, since that'll make sure they're all the same temp. Then measure the pressure, and fugacity at this point. Then you could add ice until the ice stops melting, but before the whole thing crystallizes, which will be around 0 C and measure the pressure and fugacity again. Then you could heat it up using the firewood until the water begins to boil, which will be 100C obviously... Measuring the pressure and fugacity here again. Then you could do something with the partial derivatives of fugacity relating to temperature. But I'm not sure exactly where to go with that.. Or likewise, partial derivatives of pressure relating to temperature..

 

[DeeNos]

As a scientist, the first step I would take is to use the pressure gauge to measure the pressure inside each cylinder. This will give me a starting point to work with. I would then use the fugacity meter to measure the fugacity (a measure of the escaping tendency of a gas) of the gas inside each cylinder. This will help me determine the relative amounts of different gases present in each cylinder.

Next, I would use the thermodynamics textbook to look up the properties of oxygen, helium, xenon, and uranium hexafluoride. Specifically, I would look at their boiling and melting points, as well as their densities. This information will help me narrow down the possibilities of what gases could be present in each cylinder.

Using the scale, I would weigh each cylinder and compare it to the weight of an empty cylinder. This will give me an idea of the density of the gas inside and help me confirm my initial assumptions based on the fugacity measurements.

To further confirm my findings, I would use the ice and firewood to create a temperature gradient and observe the behavior of the gas inside each cylinder. Different gases have different thermal conductivities and will behave differently when exposed to a temperature gradient.

If necessary, I would use the bubble gum and duct tape to create a makeshift gas chromatograph, which can separate and identify different gases based on their chemical properties.

As for the use of Maxwell relations, I would use them to calculate the enthalpy and entropy changes of the gases as they undergo phase changes (i.e. boiling or melting). This information can help me confirm my findings and provide more precise identification of the gases present.

In conclusion, by utilizing the tools and resources provided, as well as applying scientific principles such as gas laws and thermodynamics, it is possible to identify the contents of the cylinders with a high degree of accuracy.