What is the significant figure in 890

This drawing shows a human body system. what is the primary function of this body system?

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?

How many moles are contained in 5.6 l of h2 at stp