Question

Two hundred grams of ice at -10.0 degrees C is added to 300 grams of water at 75 degrees C. The system is kept thermally insulated from its environment. 2. You mix 50 grams of ice at 0.0 degrees C and 50 grams of steam at 100 degrees celsius. What is the equilibrium temperature? The earth receives on average 240 W of power per square meter. Using the Stefan-Boltzmann law, calculate the predicted average Earth’s temperature (assume e=1). From a web-search find the average Earth temperature and the primary reason the value you calculated is too low?

Answer 1

1. Two hundred grams of ice at -10.0 degrees C is added to 300 grams of water at 75 degrees C. The system is kept thermally insulated from its environment. We have to find the equilibrium temperature. Let t be the equilibrium temperature.

Heat required to heat the ice to 0 C + Heat required to melt it at 0 C + Heat required to raise the temperature of melted ice(water) from 0 to equilibrium temperature + Heat lost by water at 75 = 0

m1.c1.Δt1 + m1.Lf + m1.c2.Δt2 + m2c2.Δt3 = 0

0.2*2050*(0-(-10)) + 0.2*333*10^3 + 0.2*4184*(t - 0) + 0.3*4184*(t - 75) = 0

t = 11.2 deg C