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1) An aluminum calorimetry cup [m c = 0.6 kg,c c = 0.22 kcal/(kgC)] is filled wi

ID: 2273650 • Letter: 1

Question

1) An aluminum calorimetry cup [mc = 0.6 kg,cc = 0.22 kcal/(kgC)] is filled with water [mw = 2.4 kg,cw = 1 kcal/(kgC)]. It is at a temperature of 30C. A sample of an unknown substance with mass mm = 2.34 kg, originally at a temperature of 210C, is added. After a while, the temperature of the water is 35C. What is the specific heat of this material?


2) How much (in Celsius degrees) is the temperature of 1.3 kg of alcohol raised by adding 4.1 kcal of heat? The following piece of information may come in handy: specific heat of alcohol is 0.58 kcal/kgC


3) A heat engine absorbs 126 kcal of heat and exhausts 77 kcal of heat in each cycle. Calculate the efficiency (as a percentage).


4) An ideal gas heat engine operates in a Carnot Cycle between temperatures of 266 and 115

An aluminum calorimetry cup [mc = 0.6 kg, cc = 0.22 kcal/(kgC)] is filled with water [mw = 2.4 kg, cw = 1 kcal/(kgC)]. It is at a temperature of 30C. A sample of an unknown substance with mass mm = 2.34 kg, originally at a temperature of 210C, is added. After a while, the temperature of the water is 35C. What is the specific heat of this material? How much (in Celsius degrees) is the temperature of 1.3 kg of alcohol raised by adding 4.1 kcal of heat? The following piece of information may come in handy: specific heat of alcohol is 0.58 kcal/kgC A heat engine absorbs 126 kcal of heat and exhausts 77 kcal of heat in each cycle. Calculate the efficiency (as a percentage). An ideal gas heat engine operates in a Carnot Cycle between temperatures of 266 and 115degreeC. It absorbs 4250 cal per cycle at 266degreeC. What is its efficiency as a percentage? A gas is at an initial pressure of 1.24x104 Pa and occupies a volume of 0.28 m3. The (slow) addition of 23,570 cal of heat to the system causes it to expand in an isobaric manner to a volume of 0.47 m3. How much work (in joules) is done by the system? An ideal monatomic gas goes from p1 = 180 atm and V1 = 45 m3 to p2 and V2 through an adiabatic process. If p2 = 60 atm, what is V2?

Explanation / Answer

PV^ ?= P'V'^ ?

? = 1.66 for an ideal monoatomic gas


180* 45^1.66 = 60* V'^ 1.66


V'^ 1.66=30*45^1.66


V' =[30*(45^1.66) ] ^ (1/1.66)