Mendeleev · science lesson
Ideal gas: a model, not a perfect real gas
PV = nRT links pressure, volume, temperature and amount of substance in the ideal-gas model.
Start with the idea
PV = nRT links pressure, volume, temperature and amount of substance in the ideal-gas model.
A concrete example
The model works best when particle interactions become relatively weak, notably at low pressure.
Mendeleev
Mendeleev’s tip
Do not start with a formula. Identify what changes, what stays constant and which quantity you are trying to explain or calculate.
Go one step deeper
At fixed amount and volume, doubling absolute temperature in the model doubles pressure. Temperature must be in kelvins, not degrees Celsius.
Common trap
A trend or model is not an exceptionless law. Always check the quantity’s definition and the conditions being compared.
Check your understanding
Can you explain the phenomenon in your own words before looking at an equation?