November 16, 2024, 12:55:06 AM
Forum Rules: Read This Before Posting


Topic: Gas laws lab  (Read 4862 times)

0 Members and 1 Guest are viewing this topic.

Offline borg

  • Very New Member
  • *
  • Posts: 2
  • Mole Snacks: +0/-0
Gas laws lab
« on: January 04, 2007, 03:32:42 PM »

I did 3 experiments dealing with pressure/volume, volume/temperature, and pressure/temperature.
I graphed the data and found the linear relationship for each one, as well as the linear regression.

Here is my problem: I need to write Boyles' law using a constant, and both forms of Charles' law using a constant.

I know that the forms are: PV = constant; V/T = constant; P/T = constant.

The problem is that when I plug in the values, I am not getting a constant. For example, when I multiply 2 different sets of pressure and volume data, I get different numbers. And the numbers are even farther off when I use Charles' law. I am using Kelvin for temperature, so what am I doing wrong.
Thank you for any responses.

Offline Yggdrasil

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 3215
  • Mole Snacks: +485/-21
  • Gender: Male
  • Physical Biochemist
Re: Gas laws lab
« Reply #1 on: January 04, 2007, 04:04:06 PM »
PV = constant only when temperature is constant.
V/T = constant only when pressure is constant.
P/T = constant only when volume is constant.

Offline ezaga1

  • Very New Member
  • *
  • Posts: 2
  • Mole Snacks: +0/-0
Re: Gas laws lab
« Reply #2 on: January 06, 2007, 10:57:38 AM »


The reason why you are not gettiing a constant value is probably because the other factors where not kept constant.

For Boyle's Law:
PV=constant
Here temperature must be kept constant.

Charle's Law:
V/T=constant.
Here pressure must be kept constant.

If all this measures are taken properly, all your values will be correct. I hope i answered your question.

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27845
  • Mole Snacks: +1812/-412
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Gas laws lab
« Reply #3 on: January 06, 2007, 11:35:12 AM »
I graphed the data and found the linear relationship for each one, as well as the linear regression.

Quote
The problem is that when I plug in the values, I am not getting a constant.

If you got a correct relationship in the first step, you should get correct result in the second step - unless you did some other mistake. Post your results.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Offline ezaga1

  • Very New Member
  • *
  • Posts: 2
  • Mole Snacks: +0/-0
Re: Gas laws lab
« Reply #4 on: January 06, 2007, 01:32:20 PM »
From my own point of view, the main reason why your are not getting a constant value is because the others factors are not constant. For
Boyle's Law:
PV=constant, temperature must be kept constant.
Charle's:
V/T=constant, pressure must be kept constant.
Of you observe this condition your values are going to be right. I just hope this will help you.

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27845
  • Mole Snacks: +1812/-412
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Gas laws lab
« Reply #5 on: January 06, 2007, 07:40:02 PM »
From my own point of view, the main reason why your are not getting a constant value is because the others factors are not constant. For
Boyle's Law:
PV=constant, temperature must be kept constant.
Charle's:
V/T=constant, pressure must be kept constant.
Of you observe this condition your values are going to be right. I just hope this will help you.

How does this answer differs from your previous one?
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Sponsored Links