 Top

Combined Gas Law Calculator
Top
The relationship among pressure, temperature and volume of a gas sample can be expressed in a mathematical formula called the combined gas law. This law allows to predict how any of these properties of a gas will change if we change one or both of the other two.

For example, if we change the temperature of the gas inside a rigid steel cylinder, we can predict how the pressure of the gas will change.

The mathematical equation for the combined gas law is

$\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}$

In the combined gas laws the ratio of $\frac{PV}{T}$ equals a constant for a final amount of gas. The value of this constant is actually proportional to the nu
mber of moles of gas n.

## Steps for Combined Gas Law Calculator

Step 1 :

Read te problem and list out the values given.

Step 2 :

Substitute the given values in the corresponding formula to find out the unknown value.

$\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}$

## Problems on Combined Gas Law Calculator

1. ### In an autoclave, steam at 100oC generated at 1.00atm. After the autoclave is closed the steam is heated at constant volume until the pressure gauge indicates 1.13atm. What is the final temperature in the autoclave?

Step 1 :

Given data

P1 = 1.00atm
P2 = 1.13atm
T1 = 100oC = 100 + 273 = 373K

V1 and V2 are the same in this example and consequentyly cancel each other.

Step 2 :

Substitute the values in the corresponding formula to obtain the T2 value.

$\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}$

$\frac{1.00 \times}{373} = \frac{1.13}{T_{2}}$

T2 = 421K

The final temperature is T2 = 421K

or

T2 = 421 - 273 = 148oC

2. ### A gas in a fexible container has a voume of 0.50L and a pressure of 1.0atm at 393K. When the gas id heated to 500K its volume expands to 3.0L. What is the new pressure of the gas in the flexibe container?

Step 1 :

Given data

P1 = 1.0atm
V1 = 0.50L
V2 = 3.0L
T1 = 393K
T2 = 500K

P2 = ?

Step 2 :

Substitute the values in the corresponding formula to obtain the P2 value.

$\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}$

$\frac{1.0 \times 0.50}{393} = \frac{P_{2}\times3.0}{500}$

P2 = 0.21atm