Material Science

posted by .

A polystyrene ice chest contains 3 kg of ice at 0 degrees Celsius. Triangle H for melting = 3.34 x 10 to the 5 power J/kg p = 1000 kg/m cubed, CP =4190 J/ (kg K). Heat transfer is limited by conduction (k=0.06W/m K)) from the outside wall at 30 degrees Celsius. This means that temperature within the ice chest is not a function of position. Assume the heat flux (J/(sec m squared) is the same through all walls: top, sides, bottom. The walls have thickness = 4 cm and total surface area = 2400 cm squared.

Calculate heat flux (J/ (sec m squared) at the walls.

  • Material Science -

    T within wall = 0 deg C
    T outside wall = 30 deg C

    wall thickness = .04 m

    Heat power flux in Watts per m^2 = .06 W/m deg (30 deg)/.04 m = 45 Watts/m^2
    since a Watt is a Joule per second, that is the answer.

    Now the real question, which should be part B, is how long until the ice is melted :)

    45 Watts/m^2 * 2400 *10^-4 m^2 = 10.8 Watts pouring out through the walls of the box

    how many Joules to melt the ice?
    3 kg *334000 J/kg = 10^6 Joules
    so
    10.8 Joules/second * T = 10^6 Joules
    T = 92778 seconds to melt
    or
    92777/3600 = 26 hours to melt

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. physcial science

    When 1 kg of ice at 0 degrees Celsius absorbs 80 kilocalories of heat, the ice undergoes a) a change of state b) a loss of energy c) a rise in temperature d) an increase in volulme The heat of fusion of water is 80 kcal/kg. That means …
  2. Science

    You add 7800 calories of heat to a block of ice at -40 degrees celsius. the temperature of the ice rises to 0 degrees celsius. how much ice did you heat up?
  3. PHYSICS 102E

    1. How much ice at -10 degrees Celsius is required to cool a mixture of 0.1 kg ethyl alcohol and 0.1 kg water from 20 degrees Celsius to 0 degrees Celsius?
  4. Chemistry

    An 850 gram chunk of ice at 0 degrees Celsius is dropped into a container holding 1.7 kg of water at an initial temperature of 35 degrees Celsius. Due to the presence of the ice, the temperature of the water eventually drops to 0 degrees …
  5. physics

    Ice of mass 11.0 kg at 0.00° C is placed in an ice chest. The ice chest has 3.00 cm thick walls of thermal conductivity 1.00 10-5 kcal/s · m · C° and a surface area of 1.25 m2. (a) How much heat must be absorbed by the ice before …
  6. Melting Ice Chemistry

    You have an ice cube (H2O) that weighs 5 grams and is at a temperature of -10 degrees Celsius. How much heat energy(in joules) is required to melt the ice cube and raise the temperature of the resulting liquid water to 15 degrees Celsius?
  7. Material Science

    A polystyrene ice chest contains 3 kg of ice at 0 degrees Celsius. Triangle H for melting = 3.34 x 10 to the 5 power J/kg p = 1000 kg/m cubed, CP =4190 J/ (kg K). Heat transfer is limited by conduction (k=0.06W/m K)) from the outside …
  8. Material Science

    A polystyrene ice chest contains 3 kg of ice at 0 degrees Celsius. Triangle H for melting = 3.34 x 10 to the 5 power J/kg p = 1000 kg/m cubed, CP =4190 J/ (kg K). Heat transfer is limited by conduction (k=0.06W/m K)) from the outside …
  9. Material Science

    A polystyrene ice chest contains 3 kg of ice at 0 degrees Celsius. Triangle H for melting = 3.34 x 10 to the 5 power J/kg p = 1000 kg/m cubed, CP =4190 J/ (kg K). Heat transfer is limited by conduction (k=0.06W/m K)) from the outside …
  10. Physics

    Ice of mass 12.0 kg at 0.00° C is placed in an ice chest. The ice chest has 3.10 cm thick walls of thermal conductivity 1.00 10-5 kcal/s · m · C° and a surface area of 1.20 m2. (a) How much heat must be absorbed by the ice before …

More Similar Questions