The atmosphere of a planet has been determined to contain sodium at a concentration of 87.0 x 105 atoms per cm3 through the use of a ground-based spectrometer. Express this in moles per liter.
Find out the molar heat of combustion of caffeine (in kJ) when a 1.05-g sample of caffeine C8H10N4O2 burns in a constant-volume calorimeter that has a heat capacity of 7.85 kJ/K. The temperature increases from 297.50 K to 302.52 K.