Physics (heat) related question?

Question

A Thermopane window consists of two glass panes, each 0.50 cm thick, with a 1.0 cm thick sealed layer of air between. If the inside temperature is 21.5°C and the outside temperature is 0.0°C, determine the rate of heat transfer through 1.5 m2 of the window. Compare this with the rate of heat transfer through 1.5 m2 of a single 1.0 cm thick pane of glass.
Answers:
J/s (Thermopane window) =
J/s (Single pane window) =

Thanks

Answer 1

I am only in 12th grade Physics so I'm not 100% sure about my answer, but I'll try to explain how I would solve it after I researched this for a bit.

First, I always like to list my givens. Note: for this equation, as with most others, convert centimeters to meters. A is area, ΔT is change in temperature, and the Δx's represent the thicknesses (there are 3 for the 3 layers of glass, air, glass.) K is the thermal conductivity of a particular substance that you can find on http://en.wikipedia.org/wiki/Thermal_conductivity. Your book/teacher may have listed a different number for this, and I have seen many variations (but trusted wikipedia) so you probably should have looked it up in the current chapter and listed the K..

A = 1.5 m^2
ΔT = 21.5°C
Δ1x = .50 cm = .005 m
Δ2x = 1.0 cm = .01m
Δ3x = .50 cm = .005 m
K1 = .025
k2 = 1.1
K1 = .025

Now that we know these, you must plug them into this equation: http://upload.wikimedia.org/math/2/0/f/20f80e46fc929fe8b63923b32ce2f4f2.png
First, multiply A by ΔT to get 32.25. Then divide this by number by .005/1.1 + .01/.025 + .005/1.1. I ended up with 79 J/s.

For the single pane window, just plug into this equation:
J/s (Single pane window) = -KA(ΔT/Δx) = -(1.1)(1.5)(-21.5/.01) = 3500 J/s

Therefore, using significant digits:
J/s (Thermopane window) = 79 J/s
J/s (Single pane window) = 3500 J/s
The thermopane window transfers a lot less heat per second than the single window, so it is a better insulator.

Answer 2

The missing information is the heat conductance of the glass and the air. The transfer of heat will be proportional to the area of the window, the thickness of the material and the temperature differential.

Answer 3

45kg of ice, from -25c to 125c. replace of 25 to get to section replace to water, the replace to water itself then heating the water to 100c, and the flexibility as an instance it to steam, then the flexibility to warmth the steam. i favor both equations, I actually have the numbers. E = M x Cp x (replace in) T E = M x C(vaporisation) E = M x C(fussion) and should be used in this manner... a million) E = 40 5 x Cp x 25 2) E = 40 5 x Cf 3) E = 40 5 x Cp x one hundred 4) E = 40 5 x Cv 5) E = 40 5 x Cp x 25 and then upload the solutions from a million to 5 at the same time to get the total power in joules required Nb, Cp in a million, 3 and 5 should be diverse constants, dont use a similar on for all of them!