<u>Answer:</u>
<em>The amount of energy needed when water at 72 degrees c freezes completely at 0 degrees c is 
Joules</em>
<em></em>
<u>Explanation:</u>
where
= Final T - Initial T
=30125J
Q is the heat energy in Joules
c is the specific heat capacity (for water 1.0 cal/(g℃)) or 4.184 J/(g℃)
m is the mass of water
mass of water is assumed as 100 g (since not mentioned)
is the heat energy required for the phase change
=mass × heat of fusion
Total heat = 
Total Heat = 30123J + 33600J
= 63725 J
= Joules is the answer
Controlled<span>The things that are changing in an experiment are called variables. A variable is any factor, trait, or condition that can exist in differing amounts or types. An experiment usually has three kinds of variables: independent, dependent, and controlled.</span>
No i do not believe so because of the different wave lengths that are immersed from the colour spectrum
The glass rod is a piece of laboratory equipment and it is used for the mixing of <span> chemicals and other liquids.</span>
