Answer: Option (D) is the correct answer.
Explanation:
The chemical reaction equation will be as follows.
This means a new substance has been formed and a chemical change has taken place.
A chemical reaction in which heat energy is absorbed by the reactant molecules is known as an endothermic reaction.
For example, 
On the other hand, a chemical reaction in which heat energy is released by the reactant molecules is known as an exothermic reaction.
For example, 
is an exothermic reaction.
Thus, we can conclude that in the given situation the beaker most likely felt warm because a chemical reaction was producing a new substance.
Saying I have two different compounds with different molecular formula. One is compound NaCl, the other one is compound H2O. They will have different chemical properties such as their melting and boiling point. Therefore the answer is Yes.
It is an exothermic reaction
Heart: Pumps blood through the body
Bone: Provides structure
Stomach: Breaks down food into small particles
Lungs: Oxygenates blood
Chemical reaction: Ba(NO₃)₂ + H₂SO₄ → BaSO₄ + 2HNO₃.
V(H₂SO₄) = 250 mL ÷ 1000 mL/L = 0,25 L.
m(BaSO₄) = 0,55 g.
n(BaSO₄) = m(BaSO₄) ÷ M(BaSO₄).
n(BaSO₄) = 0,55 g ÷ 233,38 g/mol.
n(BaSO₄) = 0,00235 mol.
From chemical reaction: n(BaSO₄) : n(Ba(NO₃)₂) = 1 : 1.
n(Ba(NO₃)₂) = 0,00235 mol.
c(Ba(NO₃)₂) = n(Ba(NO₃)₂) ÷ V.
c(Ba(NO₃)₂) = 0,00235 mol ÷ 0,25 L.
c(Ba(NO₃)₂) = 0,0095 mol/L.
