Please a little help in this I will really appreciate it

How does a hydroelectric power plant converts energy into energy.

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?

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation: