The Combined Gas Law is the expression obtained from mathematically combining Boyle's, Charles's and Gay-Lussac's laws.

The mathematical form of the Combined Gas Law is:

(P1 x V1) / T1 = (P2 x V2 ) / T2

When any five of the six quantities in the equation are known, the sixth can be calculated. For example, we've known P1, V1, T1, P2 and V2 , the T2 can be:

T2 = P2 x V2 x T1 / (P1 x V1)

The force exerted per unit area of surface, typical pressure units are ATM, mmHg and kPa.

The measurement of space taken by a substance, it is length cubed, typical units are L, mL and m3.

A measure of the average kinetic energy of the particles in a sample of matter, expressed in terms of units or degrees designated on a standard scale. Typical units are K, F and C.

The mass of the object divided by its volume. Typical units are g/mL and kg/m3.

The formula weight of a compound is the sum of all the atomic weights of the elements present in the formula of the compound. Some text also refers it to formula mass. Typical unit is g/mol.

Mass is the amount of a substance in grams, also called weight.

The constant that appears in the ideal gas equation (PV=nRT). It is usually expressed as 0.08206 L x atm/K x mol or 8.314 J/K x mol.

The number of moles of solute dissolved in one kilogram of solvent.

The number of moles of solute in one liter of solution.

With six quantities in (P1 x V1) / T1 = (P2 x V2 ) / T2 equation, given any five, the sixth one can be calculated based on the Combined Gas Law.

In addition to the problem solving module, the "Show Work" is also displayed along with the solution to illustrate the step-by-step guide in how your problem has been solved.

This module is to compute the final pressure, volume or temperature of a gas in the known initial pressure, volume and temperature and any other two final quantities.

This is one step process, enter the known data and press **Calculate**
to output the unknowns.

1. Select **Combined Gas Law **link
from the front page or **Combined Gas**
tab from the **Gases** module.
The Input and Output screen appears.

2. In the **Input** area, enter
the three known quantities with a proper significant figure. Select
the units associated with the input.

3. Click **Calculate** to output
the answer.

4. The **Show Work** area on the
right shows you step-by-step how your problem has been solved.

To start a new problem, click **Reset**.
All Input fields will be cleared. Follow Step 1-3 again.