Answer:
The empirical formula is = 
The molecular formula = 
Explanation:
% of C = 10.13
Molar mass of C = 12.0107 g/mol
% moles of C = 10.13 / 12.0107 = 0.8434
% of Cl = 89.87
Molar mass of Cl = 35.453 g/mol
% moles of Cl = 89.87 / 35.453 = 2.5349
Taking the simplest ratio for C and Cl as:
0.8434 : 2.5349
= 1 : 3
The empirical formula is = 
Molecular formulas is the actual number of atoms of each element in the compound while empirical formulas is the simplest or reduced ratio of the elements in the compound.
Thus,
Molecular mass = n × Empirical mass
Where, n is any positive number from 1, 2, 3...
Mass from the Empirical formula = 12*1 + 3*35.5 = 118.5 g/mol
Molar mass = 237 g/mol
So,
Molecular mass = n × Empirical mass
237 = n × 118.5
⇒ n ≅ 2
The molecular formula = 
Covalent bonds consist of pairs of electrons shared by two atoms, and bind the atoms in a fixed orientation.
Answer:
Calcite
Explanation:
The chart shows that calcite is higher than gypsum, but is lower than apatite. Therefore meaning that it can scratch gypsum But not able to the same to apatite.