# Homework Help: Thermodynamics of refrigerator

1. Nov 11, 2005

### christodoulou Andrea

Electrical refrigerator contains 242 gr.Freon(mm.121).For the evaporation of 1 mole of this freon we need 4,8kcal.the capacity of the refrigerator is 120 liters.The performance coefficient is 25%.To incease the temperature of one mole of air to 1 C degree we need 7 cal.How many times must the freon recycle to decrease the temperature of the refrigerator-air to 12 C degree.

2. Nov 11, 2005

### BerryBoy

In accordance with the rules, you have to show us some working before we can help you... If you don't know where to start, I'd recommend thinking about the values you need, before starting any calculations:

i.e. How many moles of Freon have you got?
How many moles of air are 25 litres (assuming standard air pressure & temperature)?

Personally, I think this is an engineering question.

Regards,
Sam

3. Nov 11, 2005

### christodoulou Andrea

Electrical refrigerator conains 242 gr. of freon (Melecolar mass:121).For the evaporation of 1 mole of this freon are need 4,8 kcal.The capacity of the frigidaire is 120 liters and its performance coefficient is 25%.To increase the temperature of one mole of air by 1 celsius degree we need 7 cal.How many times must to the freon recycle to decrease the air of the frigidaire by 12 celsius degree.

I know tha i have 2 moles of freon.I also know the capacity and the performance coefficient but i cant continue.