Question

Please show your work!

6. (2 points) You are given 400 g of coffee (same specific heat as water) at 95.0°C (too hot to SS drink). How much ice (at 0.0°C) must be added to your coffee in order to cool it to 50.0°C? Neglect heat content of the cup and heat exchanges with the surroundings. Latent heat of fusion of ice is 3.33x10 J/kg: Specific heat of ice is 2100 J/(kgx°C). You must know the specific heat of water. Please do not ask for it. Report your answer in grams. 7. (3 points) A 20.0-g lead bullet leaves a rifle at a temperature of 87.0°C and hits a steel plate. If the bullet melts, what is the minimum speed it must have? The melting temperature of lead is 327 °C; specific heat of lead is 0.13x103 J/(kgxK); the latent heat of fusion is 22.9x103 J/kg. 8. (3 points) A traveler immerses a 180 W electric heater into a paper cup of 8 oz. of water at 68°F. (Just to remind you, 1 oz = 28.35 g; note temperature units.) The time to bring the water to a boil is: (Note: this is essentially your HW problem 28 from Ch. 11). Express your answer in minutes. 9. (3 points, EXTRA CREDIT) A 0.60 kg piece of ice at -10°C is placed in 0.30 kg of water at 50°C. How much liquid (in kg) is there in the system when it reaches thermal equilibrium? Latent heat of fusion of ice is 3.33x105 J/kg; Specific heat of ice is 2100 J/(kgx°C). You must know the specific heat of water. Please do not ask for it.

Answer 1

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