Chemical Forums

Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: annaa99 on February 09, 2020, 02:16:43 PM

Title: Need help with gas sample preparation prob
Post by: annaa99 on February 09, 2020, 02:16:43 PM

Need help with this problem, please show all steps of calculations. Appreciate!
In order to prepare a 24.0-liter volume (under ambient conditions) of chlorobenzene gas standard (C₆H5Cl; liquid density= 1.11 g/cm³) at 50 ppmv using a pre-evacuated 6.00-liter canister at 756 torr and 18 °C, (a) what volume of the 98.6 % pure chlorobenzene liquid must be injected into the canister and (b) what is the final pressure the canister containing the chlorobenzene must be pressurized to with ultrahigh purity nitrogen gas? The canister is equipped with a differential pressure gauge measuring the pressure in “psig” unit

Title: Re: Need help with gas sample preparation prob
Post by: Borek on February 09, 2020, 05:02:53 PM

Quote from: annaa99 on February 09, 2020, 02:16:43 PM

Need help with this problem, please show all steps of calculations.

Please read the forum rules (https://www.chemicalforums.com/index.php?topic=65859.0). Appreciate!

Title: Re: Need help with gas sample preparation prob
Post by: annaa99 on February 09, 2020, 07:26:50 PM

I was able to find the final pressure using (P1*V1)/ T1 = (P2*P2)/T2 equation. However, I am not sure how to find how many grams of chlorobenzene. I guess I should use density and 50 ppmv, but have not figured how to use it. I think with the known grams of chlorobenzene, I can find the number of moles and the volumes needed. Am I on the right track?