[khemauck]

Must calculate this using isothermal compressability - I assume I also need to know the original density of the substance.

Could I please have a method or some pointers on how to calculate this?

Is the equation dP = dV/V Kt enough? I am shocking at calculus and not looking for an answer to my particular question, just a general outline of how to solve such a problem.

Thanks guys!

[Enthalpy]

If the substance is a liquid or solid, no equivalent exist to some perfect gas equation, so you need experimental values of the volume compressibility or its reciprocal, the bulk modulus K (in GPa usually), or at least the sound velocity. Beware it varies with the pressure: 50bar, 350bar, 1500bar...

For a gas, under some conditions you can assimilate it to a perfect gas and then general equations exist; if not, you must choose one model and have the parameters of said gas for this model.

[khemauck]

THe question asks:

The isothermal compressibility of Bismuth at 273K is 0.0317 gPa-1. Calculate P that must be applied to change its density by 0.10%

So what assumptions could I make here? what information do I need to solve this problem?

To be honest Im not even sure what equations to use.

[Enthalpy]

Neither do I know an equation, because I'd forget it too quickly. Once you know the relation is a proportionality, intuition must do the rest.

You have units (GPa, with a big G for Giga). This must tell you what it multiplies or divides.

You have a big number: around 30 billions Pa. Whether you expect a big or a small volume variation at 1Pa should tell you how to combine the three.