<u>Explanation:</u>
Molecular formula is the chemical formula which depicts the actual number of atoms of each element present in the compound.
Empirical formula is the simplest chemical formula which depicts the whole number of atoms of each element present in the compound.
In both the formulas, the nature of atoms remains the same but the number differs.
For Example: The molecular formula of oxalic acid is
but the empirical formula of oxalic acid is 
To calculate the molecular formula, we need to find the valency which is multiplied by each element to get the molecular formula.
The equation used to calculate the valency is:

The empirical mass can be calculated from empirical formula and molar mass must be known.
Answer:
The chlorine gas and potassium bromide solution react to form liquid bromine and potassium chloride solution.
Explanation:
Chemical equation:
Cl₂(g) + KBr (aq) → KCl (aq) + Br₂(l)
Balanced chemical equation:
Cl₂(g) + 2KBr (aq) → 2KCl (aq) + Br₂(l)
This equation showed that the chlorine gas and potassium bromide solution react to form liquid bromine and potassium chloride solution.
Chlorine is more reactive than bromine it displace the bromine from potassium and form potassium chloride solution.
The given equation is balanced and completely hold the law of conservation of mass.
According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.
Explanation:
This law was given by french chemist Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.
Answer:
D because i did this last week and got it right.