What is the molar mass of a gas which has a density of .249 g/L at 20.0 degrees Celsius and a pressure of .95 atm?

Which type of orbits are found in the principal energy level n = 2 a - s b - s, f c - s, d d - s, p e - s, p, d

Which process does not require the presence of a physical substance in order to transfer heat? air in the atmosphere is heated by the ground. this warm air then rises, and cooler air falls. this is an example of what type of process? how is conduction different from radiation?

How many oxygen atoms are there in 3.15 moles of hcl manganese (iv) oxide, mno2