Helium has a density of 0.017 g/L. What is the volume of a weather balloon that contains 38 g of helium?

In a laboratory, 1.55mg of an organic compound containing carbon, hydrogen, and oxygen is burned for analysis. this combustion resulted in the formation of 1.45mg of carbon dioxide and .89 mg of water. what is the empirical formula for this compound?

In the space, show a correct numerical setup for calculating the number of moles of co2 present in 11 grams of co2

All motion is caused by force? true or false