An exothermic change will be when rain becomes sleet when the temperature falls below 0 degree Celcius. An exothermic change or reaction is a chemical reaction that release energy by light or heat. It is the opposite of an endothermic reaction. Expressed in a chemical equation: Reactants = products +energy.
The volume of a gas varies inversely with pressure is the definition of Boyle's Law.
a=b=33400 J
c=4180 J
Further explanation
Heat can be calculated using the formula:
Q = mc∆T
Q = heat, J
m = mass, g
c = specific heat, joules / g ° C
∆T = temperature difference, ° C / K
The heat to change the phase can be formulated :
Q = mLf (melting/freezing)
Q = mLv (vaporization/condensation)
Lf=latent heat of fusion
Lv=latent heat of vaporization
The heat of fusion for water at 0 °C : 334 J/g and the heat of vaporization at 100 °C : 2,230J/g
a. melting

b. freezing

c.raise the temperature(c water = 4.18 J/g C)

<span>Gather your materials. Gather the sand, salt and iron filing mixture; a magnet; a paper towel; a cup of warm water; an empty cup; and a piece of filter paper.Use the magnet to remove the iron. ...Use warm water to dissolve the salt. ...<span>Remove the sand from the salt water.</span></span>