ATPS BTPS
Alright so Back to this word problem. I fully understand how to do this now and I shall explain.
Most problems you will encounter might be in ATPS. Most likely in ATPS since that is how you will get the value.
I have found that remembering where stuff goes where is the fastest way to learn it. Don’t forget that in order to get this value you will be using the
Combined Gas LAW
P1v1 / T1 = P2V2 / T2
So both P1,V1, P2,V2 over T1,T2
So let me give a sample problem. The Barometric Pressure is 720mm HG, the patient exhales 4L and the temperature is 25 Celsius, what is the volume at BTPS?
1) Get all of your Values together.
(For ATPS, given)
P1 = 720mm Hg
V1= 4 L
T1= 25 Celsius
———————————————–
(For BTPS)
P2 = 720mm Hg
V2= ???? YOU WANT THIS.. IT IS NOT 6L because that would cancel out the problem
T2= 37 Celsius ( Body Temp is ALWAYS 37)
MOST COMMON MISTAKE PEOPLE DO including me.
What is wrong with this values?
First of all you have to Minus Water Vapor. For 37C = 47 mmHg. For 25Celsius it is 23mmHg. (given in a water vapor saturation chart) This number is important and should be memorized. Now all the temperature values has to be in Kelvin. To convert from Celsius to Kelvin just simple add +273.
Now we are good to go
(For ATPS, given)
P1 = 720mm Hg-23mm Hg
V1= 4 L
T1= 25 Celsius +273K
———————————————–
(For BTPS)
P2 = 720mm Hg - 47mmhg
V2= ???? YOU WANT THIS.. IT IS NOT 6L because that would cancel out the problem
T2= 37 Celsius+273 ( Body Temp is ALWAYS 37)
Now you have all the values and its all multiplying from here.
If you guys have any questions just feel free to ask me .