First consider and take note of the following:
1. When 2 or more finite amounts of substances are mix together (with different temperature) the final temperature is never equivalent to the initial temperature of any of the substances involved.
2. The substances meet at an equilibrium temperature.
3. Heat transfers from a higher temperature to a lower temperature.
Only choice (3) satisfies the conditions.
I've always been told that it's eight. This is only because the atom has to have the saem protons (positively charged) neutrons and electrons (negatively charged). However this does not occur with all atoms. :)
2Al + 3ZnCl₂ ----> 3Zn + 2AlCl₃
What is the coefficient in front of AlCl₃? ==>> 2
The least dense layer of the earth is the crust.