(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

We have made a standard tank in our lab. I need to calculate the uncertainty in the concentrations of the compounds we added to the tank.

2. Relevant equations

My professor indicated that I would need to use error progression to calculate an accurate uncertainty for the tank. I need some help understanding how this is done. Searching online he may have meant uncertainty propagation.

For the tank we calculated the final concentrations this way.

1) volumetric injections of compounds.

2) pressurized tank with nitrogen gas.

3) calculated volume of tank by filling with nitrogen to a measured pressure and calculating the volume using ideal gas law

4) weighed tank before and after addition of compounds and gas, so we know the weight of the nitrogen.

5) calculate concentration by converting to mols and dividing mols of compound by mols of nitrogen in the tank.

So the measurements we have are

injection volumes ex: 180 uL +- 2.5

pressure reading 1.01 bar +-0.01

Weight of N2 7.0 g +- 0.1

3. The attempt at a solution

I understand what uncertainty is, I have calculated the uncertainty in the final concentrations, but only using the uncertainty in the volumes of compound we added to the tank like +-2.5 microliters.

Is there a function in excel to calculate the uncertainty using error progression? That is what I used to calculate the tank concentrations.

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# Homework Help: Help understanding error progression.

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