In times past, on a cold winter night, it was common to bring a hot object to bed with you. Which would keep you warmer through the cold night—a 10-kg iron brick or a 10-kg jug of hot water at the same temperature? Explain.

1. (a) How much heat transfer is necessary to raise the temperature of a 0.26 -kg piece of ice from -20 °C to 130 °C, including the 20 kJ/s energy needed for phase changes? Specific heat of ice = 2.090 kJ/kg °C Specific heat of water = 4.186 kJ/kg °C Specific heat of steam = 1.520 kJ/kg °C Heat of fusion of water = 334 kJ/kg Heat of vaporization = 2256 kJ/kg (i) Heat needed to warm ice to 0 °C: Q₁: ✔KJ (ii) Heat needed to melt ice at 0 °C: Q₂: KJ (iii) Heat required to warm 0 °C water to 100 °C: Q3: KJ (iv) Heat required to vaporize water at 100 °C: Q4: KJ (v) Heat required to warm 100 °C vapor to 130 °C: Q5: KJ Total heat, Q: KJ (b) How much time is required for the entire process, assuming a constant 20.0 kJ/s rate of heat transfer? Total time, t: S

it is important not to undercook chicken, otherwise you might get very sick. The inside of the chicken has to be at a certain temperature (75 C or 165 F) to make sure it is safe. Why can’t you just wait until the outside of the chicken is at this temperature? Why isn’t the entire chicken at the same temperature while it is being cooked?

You are cold, so you cover yourself in a blanket. A half hour later, you feel much warmer. Explain in detail where the heat came from, and how the blanket helped.