100 grams of liquid nitrogen at 77K is stirred into a beaker containing 500 grams of 15 degree celsius water. If the nitrogen leaves the solution as soon as it turns to gas, how much water freezes?

Question

anonymous · Answer

none (:

anonymous · Answer

why?

anonymous · Answer

The heat of vaporization of nitrogen is 48 cal/gram. The heat of fusion of water is 80  cal/gm

anonymous · Answer

can you explain please?

anonymous · Answer

i need to understand this for an exam

anonymous · Answer

Vaporizing the N2 absorbs 48 cal/gm ( 100 gm) = 4800 cal.
That is enough cooling to bring down 500g of water by 9.6oC, 
but need to get to 0 oC to start freezing. 

Assumes N2 as vapor leaves so quickly as not to
cool water by its passage. More complex equation would include heat lost to N2 in brining it up to water temperature, and this might be enough to get some freezing.