## Tuesday, September 8, 2020

### The Math: Boyle's Law

General Chemistry Index

Where are we going with this? Getting to the current models of atomic theory didn't happen over night. This page will support the ability to use the kinetic molecular theory with the combined and ideal gas laws to explain changes in volume, pressure, moles and temperature of a gas and apply the ideal gas equation (PV = nRT) to calculate the change in one variable when another variable is changed and the others are held constant.

The Math: Boyle's Law
I told you there'd be mat!

Boyle's Law
The volume of a gas is inversely proportional to its pressure if the temperature and the number of molecules are constant.

P1V1=P2V

This is algebraically the same as a•b = c•d only with subscripts. The subscripts indicate different observations of the gas, with the 1 usually being the first observation and the 2 the second.

So, if the initial conditions are known, that makes P1V become a set number. Like 10.

If

10 = P2V

then the product of P2Vhas to always equal 10.

That means that changing either P1 of Vrequires the other to change, too. Hence:
• raising the pressure decreases the volume
• lowering the pressure increased the volume
• raising the volume decreases the pressure
• lowering the volume increased the pressure