Chemical Forums

Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Dedora on August 13, 2021, 06:39:16 PM

Title: Solving for pH using ideal gas law
Post by: Dedora on August 13, 2021, 06:39:16 PM

I had this question on my chemistry assignment:

A 250 mL sample of gaseous hydrogen bromide, measured at 23.7°C and .945 atm, was dissolved in sufficient pure water to form 250 mL of solution. What was the pH of the solution?

So I used PV=nRT to solve for n
(.945*.25)/(.0821*296.85)
n=.00969

This is where I'm unsure:
.00969/.250=.03877
-log[.03877]= 1.411

Should n be divided by 250 mL or is it a different number?

Title: Re: Solving for pH using ideal gas law
Post by: Borek on August 14, 2021, 03:03:48 AM

Looks OK.

Yes, you are told "to form 250 mL of solution", so that's the volume that should be used for concentration calculation.