100 pnts plz answer asap plz the masses of a sample of hydrogen gas and a sample of helium gas are the same: 1 g. the density of hydrogen is 0.9 g/cm3 and the density of helium is 0.00018 g/cm3. which is an accurate description of their relative volumes? a. the volumes of the hydrogen and helium samples are the same. b. the volume of the hydrogen sample is greater than the volume of the helium sample. c. the volume of the hydrogen sample is smaller than the volume of the helium sample.

Long term exposure to waves can cause sunburns and skin cancer. a) visible b) infrared c) gamma rays d) ultraviole

You are attempting to recrystallize a crude product mixture. you add the appropriate amount of hot solvent and are allowing the solution to slowly cool to room temperature. however, at room temperature no crystals have appeared, which of the following methods should be used to induce crystallization? choose all correct answers. a) place the flask in an ice bath. b) swirl the contents of the flask. c) add a small seed crystal of the desired product. d) scratch the inside of the glassware using a stir rod. it can be multiple choices

The plant food contains nh4)3po4 what tests would you run to verify the presence of the nh4 ion and the po4 ion