It'll be useful to compare the size of an atom with something familiar; how about the thickness of a sheet of paper? The diameter of a hydrogen atom is about 1 × 10-10 m and the thickness of a piece of paper is about 0.05 mm. How many hydrogen atoms stacked up would it take to equal the thickness of the paper? Give your calculations and answer in the text box below; your answer should be a whole number.

Arefrigerator uses r-134a as the working fluid and operates on the ideal vapor-compression refrigeration cycle except for the compression process. the refrigerant enters the evaporator at 120 kpa with a quality of 34 percent and leaves the compressor at 70°c. if the compressor consumes 450 w of power, determine (a) the mass flow rate of the refrigerant, (b) the condenser pressure, and (c) the cop of the refrigerator. (0.00644 kg/s, 800 kpa, 2.03)