If an element has 8 electrons, how many of them will be in the 2nd energy level

100mg magnesium reacts with 20ml of 1.0m hcl

3. how much energy in joules is required to evaporate .0005 kg of liquid ammonia to vapor at the same temperature? 4. how much energy ( in megajoules ) is given up by .75 kg of water at 0c when it freezes to form ice at 0c? 5. explain how heat works between and at critical temperatures?

Calculate the mass of 0.750 mol of the following substance. na3po4.