Can you please help

In a closed or isolated system , matter can not be created or destroyed. it can change forms but is conserved true or false

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?

What is the ph of a 0.0010 m hno3? 1.0 3.0 4.0 5.0