x.HmOne kilogram of chilled water (0 o C) is placed in a freezer which is kept a

Question

x.HmOne kilogram of chilled water (0oC) is placed in a freezer which is kept at 0oF (-18oC). Approximately how much electric energy (in kilocalories) is needed just to freeze the water if the room temperature is maintained at 75oF (24oC)? (Lice = 333 J/g; cice = 209 J/g oC.)

a. 11
b. 16
c. 33
d. 13
2.An engine is designed to obtain energy from the temperature gradient of the ocean. What is the thermodynamic efficiency of such an engine if the temperature of the surface of the water is 59oF (15oC) and the temperature well below the surface is 41oF (5oC)?
a. 3.5%
b. 31%
c. 67%
d. 17%
e. 96%
3.All real engines are less efficient than the Carnot engine because
a. the working substance does not maintain a constant pressure through the cycle.
b. they do not operate through the Otto cycle.
c. the working substance does not maintain a constant volume through the cycle.
d. the working substance does not maintain a constant temperature through the cycle.
e. they do not operate through a reversible cycle.
4.A vessel containing 5.0 kg of water at 10oC is put into a refrigerator. The 1/7 HP motor (1 HP = 746 W) runs for 5.0 minutes to cool the liquid to the refrigerator's low temperature, 0oC. What is the COP of the refrigerator?
a. 4.6
b. 6.5
c. 7.2
d. 3.6
e. 5.7
5.Find the change in entropy (in J/K) when 5.00 moles of an ideal gas undergo a free expansion from an initial volume of 20 cm3 to a final volume of 100 cm3.
a. 208
b. 67
c. 71
d. 52
e. 191

2.An engine is designed to obtain energy from the temperature gradient of the ocean. What is the thermodynamic efficiency of such an engine if the temperature of the surface of the water is 59oF (15oC) and the temperature well below the surface is 41oF (5oC)?
3.All real engines are less efficient than the Carnot engine because
4.A vessel containing 5.0 kg of water at 10oC is put into a refrigerator. The 1/7 HP motor (1 HP = 746 W) runs for 5.0 minutes to cool the liquid to the refrigerator's low temperature, 0oC. What is the COP of the refrigerator?
5.Find the change in entropy (in J/K) when 5.00 moles of an ideal gas undergo a free expansion from an initial volume of 20 cm3 to a final volume of 100 cm3.

Explanation / Answer

i already got no 1

Related Questions

Navigate

• Browse (All)
• Browse X
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.