### bar conversion

Posted:

**Tue Jan 21, 2020 6:24 pm**Could someone more clearly explain how to change the units to bar? Example 5I.1 show it but it is not very clear and I am confused

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=49&t=56956

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Posted: **Tue Jan 21, 2020 6:24 pm**

Could someone more clearly explain how to change the units to bar? Example 5I.1 show it but it is not very clear and I am confused

Posted: **Wed Jan 22, 2020 1:36 am**

The conversion of bar to atm will be given in the formula handout we are given in each test. It is mainly a difference in values of R. If you are given values in bar, use the value for R involving bar, and then convert to atm using the formula sheet.

Posted: **Wed Jan 22, 2020 8:21 am**

The formula sheet should say how to convert from atm to bar or bar to torr, so you should not worry too much about that.

Posted: **Wed Jan 22, 2020 9:18 am**

In example 5I.1, they want you convert the partial pressures PH2 and PCl2 from mPa (which is given) to bar.

Partial pressure of H2 = 4.2 mPa and Cl2 = 8.3 mPa

It's also given that 1 bar = 10^5 Pa

However, we are given partial pressures in mPa. Knowing that there are 1000 mPa in 1 Pa, you can convert 4.2 mPa and 8.3 mPa to 4.2x10^-3 Pa and 8.3x10^-3 Pa.

Now that you know the Pa, you can convert the units to bar.

Partial pressure of H2 = 4.2 mPa and Cl2 = 8.3 mPa

It's also given that 1 bar = 10^5 Pa

However, we are given partial pressures in mPa. Knowing that there are 1000 mPa in 1 Pa, you can convert 4.2 mPa and 8.3 mPa to 4.2x10^-3 Pa and 8.3x10^-3 Pa.

Now that you know the Pa, you can convert the units to bar.

Posted: **Sun Jan 26, 2020 2:46 pm**

I noticed this on the formula sheet thank you for letting me know!

Posted: **Sun Jan 26, 2020 6:46 pm**

Also, if you are given the concentration and need to convert into bar, torr, etc., you would use the PV = nRT equation with the corresponding R.