You want to use an electric stove to heat some water. You place a pot filled with 1500 g of water at room temperature (25 °C) on the stove (the charaterisitics of the pot can be neglected). In order to heat the water faster, you also use an electric beater which does 120 J of work per second. After 9 minutes the water starts boiling (100 °C). Specific heat capacity of water is 4.2 J/(g*°C). What was the change of thermal energy in the water? 472500 472500 How much energy Q was thermally transfered from the stove only to the water? 64800 J X 64800 By how much has the energy of the surroundings changed? J X

A sample of 5.25 kilograms of water at 6.00°C is placed in the freezer. Assuming all energy removed from the freezer is removed from the water, how long does the 1/5 horsepower (HP) motor (1 HP = 746 Watts) have to run to cool all of the liquid to ice at 0.00°C? The freezer has a COP of 5.00.

A block of iron (c=448.00 J/kj°C) initially at temperature 6.00°C is dropped into an insulated container filled with 15.71kg of water ( cwater=4186.00 J/kg°C) at 93.00°C. They come to equilibrium at a final temperature of 39.00°C. Determine the mass of the iron block. _____kg Determine the magnitude of thermal energy Q transferred between the two substances. ______kJ

A 155 g copper bowl contains 230 g of water, both at 20.0°C. A very hot 300 g copper cylinder is dropped into the water, causing the water to boil, with 4.05 g being converted to steam. The final temperature of the system is 100°C. Neglect energy transfers with the environment. (a) How much energy (in calories) is transferred to the water as heat? 8.6 X kcal (b) How much energy (in calories) is transferred to the bowl? 55 X kcal (c) What is the original temperature of the cylinder? 553.6 X °C Did you use the idea of conservation of energy? That is, did you equate the sum of the energy transfers to zero? For the bowl and cylinder, did you substitute the expression relating an energy transfer, the specific heat, the mass, and the temperature change? For the water, did you use the same expression to get the water to the boiling point? Did you also include an expression for the heat of vaporization? Did you use the given final temperature for each of the three materials?