Ibuprofen, a common pain remedy, has an empirical formula of c7h9o and a molar mass of approximately 218.078 grams per mole. what is the molecular formula of ibuprofen?

To prevent the presence of air, noble gases are placed over highly reactive chemicals to act as inert "blanketing" gases. a chemical engineer places a mixture of noble gases consisting of 4.37 g of he, 13.36 g of ne, and 36.65 g of kr in a piston-cylinder assembly at stp. calculate the partial pressure in torr of kr.