Martina has a sample of an unknown substance, she measures the substance, its mass is 13.5 grams, and its volume is 5cm^3 which metal might her sample be made of? silver density: 10.49 g/cm^3 copper density: 8.96 gm/cm^3 iron density: 7.87 g/cm^3 aluminum density: 2.7 g/cm^3

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?