Please help !!! Which of the following is a mathematical statement of the first
ID: 1574612 • Letter: P
Question
Please help !!! Which of the following is a mathematical statement of the first law of thermodynamics? 10. 11. If the volume of a gas is doubled without changing its temperature, the pressure of the gas is a. reduced to 1/4 of the original value c. doubled b. reduced to 1/2 of the original value d. quadrupled 12. Work is a positive quantity? a when the gas has work done on it b. when the gas does work s when the gas absorbs heat d. when the gas loses heat 13. A 2-mole ideal gas system is maintained at a constant volume of 4 liters. If S0 J of heat is added, what is the increase in internal energy of the system? a. zero b. 50 J c. 100 J d. 200 J 14. If 200 J of work is done on a system and 293 J of heat is extracted from the system, what is the change in internal energy of the system? a. -93J b. 93 J c. -493 J d. +493 J 15. A 1.0 kg block of ice at O°C and 1 atm melts completely to water. What is its change in entropy? a. 3340 J/k b. 2170 J/K d. 1220 J/K 16. Two moles of an ideal gas at T 350 K expand isothermally from an initial volume d. -24.6 J/K 17. A heat engine whose efficiency is 25 % does 500 J of work each cycle. How much of 20L to a final volume of 60 L. The change in entropy during this change is b. 18.3 J/K c. 20.4 J/K heat is rejected to the surroundings (low temperature reservoir) each cycle? a. 500 J b. 1000 J c. 1500 J d. 2000 J 18. Spontaneous heat flow from a warmer body to a colder body is in violation of which of the following laws of thermodynamics? a. first law c. both a and b b. second law d. neither a nor b 19, The efficiency of an ideal (Carnot) engine is 30%. What is the temperature of the cold reservoir if the temperature of the hot reservoir is 500 K? a. 147 K b. 350 K c. 269 K d. 231 K 20. A refrigerator has a coefficient of performance of 4.0. How much heat is exhausted to the hot reservoir when 400 kJ of heat are removed from the cold reservoir? d. 80kJ a. 500 kJ b. 400 kJ c. 100 kJExplanation / Answer
Q: 10 option C: change in internal energy is equal to heat added - work done
Q: 11 P1V1= P2V2
V2= 2V1
P1 ( V1) = P2 ( 2V1)
P2= P1/ 2 , option b
Q: 12, when the work is done by the system: option a
Q: 13 : Q = E internal + Work done
but work done is 0 at constant volume, so change in internal energy = 50 J