This program is Copyright © 1978 by HewlettPackard and is used here by permission. This program was originally published in "HP33E Student Engineering Applications".
This program is supplied without representation or warranty of any kind. HewlettPackard Company and The Museum of HP Calculators therefore assume no responsibility and shall have no liability, consequential or otherwise, of any kind arising from the use of this program material or any part thereof.
Many gases obey the ideal gas laws quite closely at reasonable temperatures and pressures. This program calculates any one of the four variables when data for the other three and the universal gas constant are entered. Likewise the value of the universal gas constant can be determined by entering data for the four variables.
Equation:
PV = nRT
Where:
P is the absolute pressure V is the volume n is the number of moles present R is the universal gas constant T is the absolute temperature 
Value of R 
Units of R 
Units of P 
Units of V 
Units of T 
8.314 
Nm/g mole K 
N/m^{2} 
m^{3}/g mole 
K 
83.14 
cm^{3}bar/g mole K 
bar 
cm^{3}/g mole 
K 
82.05 
cm^{3}atm/g mole K 
atm 
cm^{3}/g mole 
K 
0.08205 
latm/g mole K 
atm 
l/g mole 
K 
0.7302 
atmft^{3}/lb mole°R 
atm 
ft^{3}/lb mole 
°R 
10.73 
psift^{3}/lb mole°R 
psi 
ft^{3}/lb mole 
°R 
1545 
psfft^{3}/lb mole°R 
psf 
ft^{3}/lb mole 
°R 
Remarks:
Step 
Instructions 
Input Data/Units 
Keys 
Output Data/Units 
1 
Enter program 

2 
Set display and initialize 

f FIX 2 f PRGM 

3 
Input variables* 




Pressure 
P 
ENTER 


Volume 
V 
R/S 


Number of moles 
n 
ENTER 


Universal gas constant** 
R 
ENTER 


Absolute temperature 
T 


4 
a) To calculate P or V 

R/S 
P or V 

or 




b) To calculate n, R or T 

R/S R/S 
n, R or T 
5 
To change conditions: 




a) Go to step 3, or, 




b) Store new variable in proper register (see register contents) and store 1 in register of variable to be calculated, then, 




for P or V 

GSB 16 
P or V 

or, 




for n, R or T 

GSB 16 R/S 
n, R or T 

* Note: variables must be input in order shown. Input zero for variable to be calculated. 




** Be sure R is in units compatible with units of variables. 



0.63 moles of air are enclosed in 25000 cm^{3} at 1200K. What is the pressure in bars? In atmospheres? Assume and ideal gas. (R = 83.14 cm^{3}bar/g moleK or 82.05 cm^{3}atm/g moleK)
Keystrokes Display f FIX 2 f PRGM 0 ENTER 25000 R/S .63 ENTER 83.14 ENTER 1200 R/S 2.51 (bars) 82.05 STO 4 GSB 16 2.48 (atm)
LINE CODE KEYS 00 f CLEAR PRGM 01 12 28 GSB 28 02 23 2 STO 2 03 22 Roll dn 04 12 28 GSB 28 05 23 1 STO 1 06 22 Roll dn 07 74 R/S 08 12 28 GSB 28 09 23 5 STO 5 10 22 Roll dn 11 12 28 GSB 28 12 23 4 STO 4 13 22 Roll dn 14 12 28 GSB 28 15 23 3 STO 3 16 24 3 RCL 3 17 24 4 RCL 4 18 61 x 19 24 5 RCL 5 20 61 x 21 24 1 RCL 1 22 24 2 RCL 2 23 61 x 24 71 ÷ 25 74 R/S 26 15 3 g 1/x 27 13 00 GTO 00 28 15 61 g x!=0 29 15 12 g RTN 30 22 Roll dn 31 1 1 32 15 12 g RTN
R1 P R2 V R3 n R4 R R5 T
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