The question is a enthalopy problem where the enthalopy has to be caluculated per mole at the end. I understand how to calculate the enthalopy change, but I can't seem to calculate the number of moles in the question to be able to calculate the change in enthalapy per mole. I'm given 50.0 cm^3 of 1.00 mol dm^-3 of a substance. The answer is given so I know it's 0.05 moles but how was that calculated? And also why is it dm^-3 and not dm^3? I know that a cm is a hundreth of a meter and a dm is 10cm/meter or is it? I'm really confused about my units (especially the cubed parts) so if someone can clarify all this it would be greatly appreciated.