How many grams of water can be cooled from 33 ∘c to 15 ∘c by the evaporation of 50 g of water? (the heat of vaporization of water in this temperature range is 2.4 kj/g. the specific heat of water is 4.18 j/g⋅

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1595 g

Explanation: -

Heat of vaporization = 2.4 Kj/ g

Mass of water to be vaporized = 50 g

Heat released = Mass of water to be vaporized x Heat of vaporization

= 50 g x 2.4 KJ /g

= 120 KJ

= 120000 J

Initial temperature= 33+273= 306 K

Final temperature =15+273=288 K

Change in temperature required = T = 306 - 288 = 18 K

specific heat of water is 4.18 J / g K

Mass of water that can be cooled = Total heat / (specific heat of water x Change in temperature)

= 120000 J / ( 4.18 J / g K x 18 K)

= 1595 g

pure substance: iron,copper

impure substance: water,charcoal

in chemistry, adhesion and cohesion are attractive forces that exist between molecules. they hold the molecules together from each other. they are different in that adhesive force exists between molecules of different substance while cohesive force happens between molecules of same substance.

adhesion between water and glass causes water molecules at the edge of water and glass interface to climb up the wall in a narrow glass tube. this is called capillary action. cohesion is what gives glass its shape and causes water to form a droplet.