Question What is the molarity of a 400 mL solution containing 0.60 moles of NaCl?
1 answer:
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This problem is providing us with the chemical equation for the decomposition of water to hydrogen and oxygen, the involved bond energies and asks for the total energy of the reaction as well as whether it is endothermic or exothermic. At the end, one comes to the conclusion that it is exothermic because the total energy is -425 kJ.
<h3>Bond energy:</h3>In chemistry, bond energies are defined as the necessary energy to break a bond between two atoms. In this case, we see that water, H2O has two H-O bonds and hydrogen and oxygen have two H-H and one O=O bonds, respectively.
Thus, we write the following heat equation, which comprises the aforementioned bond energies and the stoichiometric coefficients in the reaction:
Hence, we plug in the given bond energies to obtain:
Where the negative suggests this is an exothermic reaction as it releases energy (negative enthalpy).
Learn more about bond energies: brainly.com/question/26141360
The question is incomplete, here is the complete question:
A reaction
has a standard free-energy change of -4.88 kJ/mol at 25°C
What are the concentrations of A, B, and C at equilibrium if at the beginning of the reaction their concentrations are 0.30 M, 0.40 M and 0 M respectively?
<u>Answer:</u> The equilibrium concentrations of A, B and C are 0.117 M, 0.217 M, 0.183 M respectively.
<u>Explanation:</u>
Relation between standard Gibbs free energy and equilibrium constant follows:
where,
= Standard Gibbs free energy = -4.88 kJ/mol = -4880 J/mol (Conversion factor: 1 kJ = 1000 J)
R = Gas constant =
T = temperature =
= equilibrium constant of the reaction
Putting values in above equation, we get:
We are given:
Initial concentration of A = 0.30 M
Initial concentration of B = 0.40 M
Initial concentration of C = 0 M
The chemical reaction follows:
<u>Initial:</u> 0.30 0.40 0
<u>At eqllm:</u> 0.30-x 0.40-x x
The expression of equilibrium constant for the above reaction follows:
We are given:
Putting values in above equation, we get:
Neglecting the value of x = 0.657, because change cannot be greater than the initial concentration
So, equilibrium concentration of A =
Equilibrium concentration of B =
Equilibrium concentration of C =
Hence, the equilibrium concentrations of A, B and C are 0.117 M, 0.217 M, 0.183 M respectively.