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
One mole of
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
Atomic mass of
Atomic mass of
Now,
110.978 g of
75.9 g of
Hence,
The total number of moles in 75.9g of
According to <span>Avogadro's number,
1 mole = 1 * </span>
0.6839 moles = 0.6839 *
Ans: Number of molecules in 75.9g of
-i