or many years drinking water has been cooled in hot cli- mates by evaporating it from the surfaces of canvas bags or porous clay pots. How many grams of water can be cooled from 35 to 20 °C by the evaporation of 60 g of water?the heat of evaporation of water in this temperature rsnges is 2.4 kj/g. the specific heat capacity of water is 4.18 j/g K.

Answer :

Answer:

2,296.7 grams of water can be cooled from 35°C to 20 °C by the evaporation of 60 g of water.

Explanation:

The heat of evaporation of water = [tex]H_e=2.4 kJ/g[/tex]

Mass of water evaporated , m= 60 g

Amount of heat required to evaporate 60 grams of water :Q

[tex]Q = H_e\times m=2.4 kJ/mol\times 60 =144 kJ[/tex]

Amount of heat lost to condense water 35 to 20 °C = -Q = -144 kJ = 144,000 J

Mass of water = m

Specific hat of water = c =  4.18 J/g K

Initial temperature = [tex]T_1=35^oC=308.15 K[/tex]

Final temperature = [tex]T_2=20^oC=293.15 K[/tex]

Change in temperature = [tex]\Delta T=T_2-T_2[/tex]

[tex]Q'=mc\Delta T[/tex]

[tex]m=\frac{Q'}{c\Delta T}=\frac{-144,000 J}{4.18 J/g K\times (293.15 K-308.15 K)}[/tex]

m = 2,296.7 g

2,296.7 grams of water can be cooled from 35°C to 20 °C by the evaporation of 60 g of water.

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