7. Calculate the amount of energy required heat 100.g to
H2O(s) changes to H2O(l) at 0°C

33300J

Explanation:

Given parameters:

Mass of ice  = 100g

Unknown:

Amount of energy = ?

Solution:

This is a phase change process from solid to liquid. In this case, the latent heat of melting of ice is 3.33 x 10⁵ J/kg.

 So;

            H  = mL

m is the mass

L is the latent heat of melting ice

  Now, insert the parameters and solve;

            H = mL

 mass from gram to kilogram;

            100g gives 0.1kg

  H = 0.1 x 3.33 x 10⁵ = 33300J

explanation: it gains negative electrons, therefore becoming negatively charged. as charge cannot be created, nor destroyed, only transferred, this leaves the wool positive. now that they have opposite charges, the two items attract.

a:

by the combination of an unlimited number of elements