How to find number of moles if only molar mass is given? (mass is not given; n=m/m)

What is the maximum number of electrons that an atomic orbital can contain?

A50.0g sample of liquid water at 0.0 c ends up as ice at -20.0 c. how much energy is involved in this change?

Two metal blocks that have slightly different temperatures are placed next to one another. after five minutes, they both have lower but equal temperatures. according to the law of conservation of energy, what  most likelyhappened? energy was created inside the blocks.energy was destroyed inside the blocks.energy was absorbed into the blocks from outside the system.energy was transferred from the warmer block to the cooler block.