Explanation:
thermal changes are those in which heat exchange is involved like endothermic and exothermic
while in chemical changes collision between the reactant occurs which result into product
First, you need to find:
One mole of

is equivalent to how many grams?
Well, for this you have to look up the periodic table. According to the periodic table:
The atomic mass of Calcium Ca = 40.078 g (See in group 2)
The atomic mass of <span>Chlorine Cl = 35.45 g (See in group 17)
</span>
As there are two atoms of Chlorine present in

, therefore, the atomic mass of

would be:
Atomic mass of

= Atomic mass of Ca + 2 * Atomic mass of Cl
Atomic mass of

= 40.078 + 2 * 35.45 = 110.978 g
Now,
110.978 g of

= 1 mole.
75.9 g of

=

= 0.6839 moles.
Hence,
The total number of moles in 75.9g of

= 0.6839 moles
According to <span>Avogadro's number,
1 mole = 1 * </span>

molecules
0.6839 moles = 0.6839 *

molecules =

molecules
Ans: Number of molecules in 75.9g of
=
molecules
-i
<span>Energy = Mass * heat capacity * temperature change so,
</span>The energy added is 435 J and the temperature has to increase since the energy is added.
<span>435 J = 10.0 g * 0.89 J/gC * temperature change </span>
<span>Temperature change = 48.9 C </span>
<span>The initial temperature is 25.0 C, the final temperature is 25.0 C + 48.9 C = 73.9 C.</span>