It will depend on the chemical, if it's a chemical compound, yes it can be decomposed chemically into simpler substances, further elements that constitute or make up the given compound.
Mixtures are separated by physical means as there are still separate entities as the substances required to make the mixture do not chemically combine or become altered chemically.
Elements cannot be decomposed into simpler substances as the simplest substance of matter is an element itself. This cannot be decomposed by chemical means.
Answer:

Explanation:
The limiting reactant is the reactant that gives the smaller amount of product.
Assemble all the data in one place, with molar masses above the formulas and masses below them.
M_r: 39.10 80.41 2.016
2K + 2HBr ⟶ 2KBr + H₂
m/g: 5.5 4.04
a) Limiting reactant
(i) Calculate the moles of each reactant

(ii) Calculate the moles of H₂ we can obtain from each reactant.
From K:
The molar ratio of H₂:K is 1:2.

From HBr:
The molar ratio of H₂:HBr is 3:2.

(iii) Identify the limiting reactant
HBr is the limiting reactant because it gives the smaller amount of NH₃.
b) Excess reactant
The excess reactant is K.
c) Mass of H₂

<span>Answer:
Molecular:
HC2H3O2(aq) + KOH(aq) --> KC2H3O2(aq) + H2O(l)
Complete ionic:
HC2H3O2(aq) + K+(aq) + OH-(aq) --> K+(aq) + C2H3O2-(aq) + H2O(l)
Net Ionic:
HC2H3O2(aq) + OH-(aq) --> C2H3O2-(aq) + H2O(l)</span>
It is A , each sodium ion is surrounded by one chloride ion . the explanation is because Chlorine needs one more electron to have a full outer most shell , and sodium has one electron in its outer most shell .