Some molecules have the exact same molecular formula but when you look at them you can see that they are shaped differently,
An example being coal and diamond, both are made of pure carbon but the reason why diamond is so much stronger than coal is because of its lattice structure.
So, basically, it might have different quantities, such as Carbon Dioxide (CO2) and Carbon Monoxide (CO), which are both made up of Carbon and Oxygen, but Carbon Monoxide has less oxygen. And they both have different properties, like CO is poisonous.
