# What are the gas laws formulas?

##### 2 Answers

There are a few

#### Explanation:

Boyle's law:

Charles' law:

Pressure law:

Avogradro's law

Ideal gas law:

These may also apply:

Key:

You only need one for ideal gases:

#color(blue)(|barulstackrel(" ")(" "PV = nRT" ")|)# where:

#P# is pressure in#"atm"# .#V# is volume in#"L"# .#n# is mols of ideal gas.#R = "0.082057 L"cdot"atm/mol"cdot"K"# is the universal gas constant for these pressure and volume units.#T# is the temperature in#"K"# .

*If you wish to utilize other ones, you must examine the question wording and determine the environmental conditions, then set up your initial and final states. This is how you will be expected to do it on exams.*

**CONSTANT PRESSURE AND MOLS OF GAS**

In this case your volume and temperature vary.

#PV_1 = nRT_1#

#PV_2 = nRT_2#

Thus, dividing these gives

#V_1/V_2 = T_1/T_2#

or

#color(blue)(V_1/T_1 = V_2/T_2)# ,

known as **Charles's Law**.

**CONSTANT TEMPERATURE AND MOLS OF GAS**

In this case your pressure and volume vary.

#P_1V_1 = nRT#

#P_2V_2 = nRT#

Thus, we get

#color(blue)(P_1V_1 = P_2V_2)# ,

known as **Boyle's Law**.

**CONSTANT PRESSURE AND TEMPERATURE**

In this case your volume and mols vary such that your molar volume is constant for the same gas:

#PV_1 = n_1RT#

#PV_2 = n_2RT#

Therefore,

#V_1/V_2 = n_1/n_2#

or

#color(blue)(V_1/n_1 -= barV_1 = V_2/n_2 -= barV_2)#

otherwise known as **Avogadro's principle**.

**CONSTANT VOLUME AND MOLS OF GAS**

Here we have varying pressure and temperature:

#P_1V = nRT_1#

#P_2V = nRT_2#

Thus,

#P_1/P_2 = T_1/T_2#

or

#color(blue)(P_1/T_1 = P_2/T_2)#

sometimes known as **Gay-Lussac's Law**.