Question

A steel sphere has an inner volume of 4 liters and weighs 15 lbs when empty. it also has a hole in the top that is 3.33 mm in diameter. the sphere is half filled with ice and the other half is filled with air. the whole system starts at STP. (you do not need the specific heat of air )

1. what is the total energy needed to raise this system to 100 degrees C?

A 999 W heater is then applied to the steel sphere. Assume all parts of the system gain energy at an equal rate

2. what is the temperature of the air and steel when the water reaches 100 degrees C?

3. if the pressure of the air in the sphere is always 1 atm, what is the mass transfer rate of the air over time it takes to heat the water to 100 degrees C? is it gaining or losing mass?

4. the heater is shut off and the system reaches an equilibrium temperature. what is this temperature?

5. if the system is allowed to cool what is the initial rate at which it would cool back down to STP? Assume the surface area of the sphere is around 0.138 m^2 and the air thickness that surrounds the sphere is 2.22 cm.

6. how long would it take to reach 0 degrees C?

Answer #1

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