Q 40

An 920-g piece of iron at 100°C is dropped into a calorimeter of negligible heat capacity containing 50 g of ice at 0°C and 92 g of water,also at 0°C.What is the final temperature of the system? The specific heat of iron is 448 J/kg ∙ K,that of water is 4186 J/kg ∙ K,and the latent heat of fusion of water is 33.5 × 10^{4} J/kg.
A)0°C
B)11°C
C)14°C
D)24°C
E)32°C

Q 41

A 360-g metal container,insulated on the outside,holds 180.0 g of water in thermal equilibrium at 22.0°C.A 24.0-g ice cube,at the melting point,is dropped into the water,and when thermal equilibrium is reached the temperature is 15.0°C.Assume there is no heat exchange with the surroundings.For water,the specific heat capacity is 4190 J/kg ∙ K and the heat of fusion is 3.34 × 10^{5} J/kg.What is the specific heat capacity of the metal of the container?
A)1700 J/kg ∙ K
B)970 J/kg ∙ K
C)2300 J/kg ∙ K
D)2800 J/kg ∙ K
E)3300 J/kg ∙ K

Q 42

Two experimental runs are performed to determine the calorimetric properties of an alcohol which has a melting point of -10.0° C.In the first run,a 200-g cube of frozen alcohol,at the melting point,is added to 300 g of water at 20.0°C in a styrofoam container.When thermal equilibrium is reached,the alcohol-water solution is at a temperature of 5.0°C.In the second run,an identical cube of alcohol is added to 500 g of water at 20.0°C and the temperature at thermal equilibrium is 10.0°C.The specific heat capacity of water is 4190 J/kg ∙ K.Assume no heat is exchanged with the styrofoam container and the surroundings.What is the heat of fusion of the alcohol?
A)5.5 × 10^{4} J/kg
B)6.3 × 10^{4} J/kg
C)7.1 × 10^{4} J/kg
D)7.9 × 10^{4} J/kg
E)8.7 × 10^{4} J/kg