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 = 
B, homeostasis. “Homeostasis is the state of steady internal, physical, and chemical conditions maintained by living systems.”
Answer: The change in enthalpy will be -13.
Explanation:-
Endothermic reactions are those in which heat is absorbed by the system and exothermic reactions are those in which heat is released by the system.
for Endothermic reaction is positive and
for Exothermic reaction is negative.

When 1 mole of A combining with 1 mole of B to produce 3 moles of C
Thus as the stoichiometry has got half of the original , enthalpy of the reaction will also get half.
Thus for reaction :

Thus the change in enthalpy will be -13.
Attached to this answer is the format of Isotope Notation that you can use for future reference. <em>(Please open)</em>
There are
8 Protons. The Atomic Number is the same number of an element's proton.
If you can see in the format, the mass number is calculated by adding the atomic number/protons and neutrons.
Mass number = 8 + 11Mass number = 19The image of the final answer is attached as well.
Answer:
Normality N = 0.2 N
Explanation:
Normality is the number of gram of equivalent of solute divided of volume of solution, where the number of gram of equivalent of solute is weight of the solute divided by the equivalent weight.
Normality is represented by N.
Mathematically, we have :

Given that:
number of gram of equivalent of solute = 90 milliequivalents 90 × 10⁻³ equivalent
volume of solution (HCl) = 450 mL 450 × 10⁻³ L

Normality N = 0.2 N