Answer:
4
Explanation:
Avogadro’s number represent the number of the constituent particles which are present in one mole of the substance. It is named after scientist Amedeo Avogadro and is denoted by
.
Also, it is the number of particles in exactly 12.000 g of isotope carbon 12.
Avogadro constant:-
Hence,
Mass of
= 131.293+ n18.998 g
So,
molecules have a mass of 131.293+ n18.998 g
Also,
molecules have a mass of
g
So,
molecules have a mass of
g
Also, given mass = 0.172 g
Thus,




<u>Thus, value of n is 4.</u>
Answer:
Atomic Number = 3.
Explanation:
The number of protons determines the atomic number. Basically the number of protons is the exact same as the atomic number.
Protons 3 = Atomic number 3
Answer : This reaction is an exothermic reaction.
Explanation :
Endothermic reaction : It is defined as the chemical reaction in which the energy is absorbed from the surrounding.
In the endothermic reaction, the energy of reactant are less than the energy of product.
Exothermic reaction : It is defined as the chemical reaction in which the energy is released into the surrounding.
In the exothermic reaction, the energy of reactant are more than the energy of product.
Enthalpy of reaction : It is the difference between the energy of product and the reactant. It is represented as
.
The balanced chemical reaction will be:

From the reaction we conclude that the heat energy is released during the reaction that means this reaction is an exothermic reaction.
Hence, the reaction is an exothermic reaction.
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