How many kilojoules are required to heat 0.500 g of water from 20.3 degrees celcius to 29.7 degrees celcius ? how many calories? show your work and watch sig figs.

Amount of heat = mass of water * specific heat (temperature change

)

= 0.500 g * 4.184 J / g-C ( 29.7 -20.3 )C

= 19.6648 J  

= 0.0197 KJ

And  

1 cal = 4.186798 J

19.6648 J * 1 cal / 4.186798 J =4.70 cal

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.