Liquid ammonia is used in ice factory for making ice from water. If water at 20^@C is to be converted into 2 kg ice at 0^@C, how many grams of ammonia are to be evaporated? ( Given: The latent heat of vapourization of ammonia = 341 cal/ g)

Liquid ammonia is used in ice factory for making ice from water. If wa

1.	Liquid ammonia is used in ice factory for making ice from water. If water at 20^@C is to be converted into 2 kg ice at 0^@C, how many grams of ammonia are to be evaporated? ( Given: The latent heat of vapourization of ammonia = 341 cal/ g)
Answer» Solution :Given:Latent heat of melting of ice =`L_"melt"`=80 cal/G Latent heat of VAPOURIZATION of ammonia = 341 cal/g Temperature of liquid water =`20^@C` Temperature of ice = `T_"ice"=0^@C` Solution:Heat RELEASED during conversion of liquid water into water at `20^@ C , =m_(H_2O) xx L_"melt"` = 2 x 100 x 80 ....(i) Heat released during conversion of water of `20^@`C into ice at `0^@C` `=m_(H_2O) xx DeltaT xxC` = 2 x 1000 x (20 - 0) x 1 = 2 x 1000 x 20 ...(ii) Total heat gained by ice, =(2 x 1000 x 80 ) + ( 2 x 1000 x 20 ) [ from (i) and (ii) ] =2,00,000 cal AMOUNT of ammonia required to be evaporated `m_"Ammonia " xx L_"vap of ammonia " `=2,00,000 `m_"Ammonia"=200000/341`=586.4g 586.4 g of ammonia are to be vaporated .