How many grams of oxygen would be produced by the electrolysis of 72.0 grams of water ? 2h2o--> o2+2h2 (must be made to fit into the chart underneath #8)

Compare the valence electron configuration of the nobles gas elements seen here. what statement is correct?

The volume of helium in a blimp is 6.28 x 10^9 millimeters. the density of helium in the blimp is .1786 kilogram/meter^3. find the mass of the helium in the blimp.

Large helium-filled balloons are used to lift scientific equipment to high altitudes. what is the pressure inside such a balloon if it starts out at sea level with a temperature of 10.0ºc and rises to an altitude where its volume is twenty times the original volume and its temperature is – 50.0ºc ?