To calculate for the final temperature, we need to remember that the heat rejected should be equal to the absorbed by the other system. We calculate as follows:
Q1 = Q2
(mCΔT)1 = (mCΔT)2
We can cancel m assuming the two systems are equal in mass. Also, we cancel C since they are the same system. This leaves us,
(ΔT)1 = (ΔT)2
(T - 80) = (0 - T)
T = 40°C
Let's write the equation

According to law of conservation of mass .
- Mass of products=Mass of reactants
Let required value be x




We have as a reagent a salt, lead nitrate (Pb(NO3)2), and an unknown solution that gives us as a product lead chloride (PbCl2). That is, the solution must contain chlorine.
If a chlorine solution is used we will have the following reaction:

So, with a chlorine solution, we will have a white precipitate of lead chloride.
Lakes, oceans, glaciers, clouds, etc. It categorizes all forms of water on earth.
hydro = water