Answer:
0.24mole
Explanation:
Given parameters:
Number of molecules = 14.35 x 10²² molecules;
Unknown = number of moles of H₃PO₄
A mole of a substance is the quantity of matter that contains the avogadro's number of particles.
This number is given as 6.02 x 10²³ particles. The particles can be atoms, molecules, protons, electrons e.t.c
6.02 x 10²³ molecules is contained in 1 mole of any substance
14.35 x 10²² molecules will contain: = 0.24mole
Answer : The enthalpy change of reaction is -1800 kJ
Explanation :
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The given final reaction is,
The intermediate balanced chemical reaction will be,
(1)
(2)
First we will multiply reaction 1 by 2 and reverse reaction of reaction 2 by 3 then adding both the equation, we get :
The expression for final enthalpy is,
where,
n = number of moles
Therefore, the enthalpy change of reaction is -1800 kJ