Answer:
The correct answer is: 1.035 x 10⁻³ M
Explanation:
The dissociation equilibrium for acetic acid (CH₃COOH) is the following:
CH₃COOH(aq) ↔ CH₃COO⁻(aq) + H⁺(aq) Kc = 1.8 x 10⁻⁵
The expression for the equilibrium constant (Kc) is the ratio of concentrations of products over reactants. The products are acetate ion (CH₃COO⁻) and hydrogen ion (H⁺) while the reactant is acetic acid (CH₃COOH):
![Kc=\frac{[CH_{3} COO^{-} ][H^{+} ]}{[CH_{3} COOH]}= 1.8 x 10^{-5}](https://tex.z-dn.net/?f=Kc%3D%5Cfrac%7B%5BCH_%7B3%7D%20COO%5E%7B-%7D%20%5D%5BH%5E%7B%2B%7D%20%5D%7D%7B%5BCH_%7B3%7D%20COOH%5D%7D%3D%201.8%20x%2010%5E%7B-5%7D)
Given: [CH₃COOH]= 0.016 M and [CH₃COO⁻]= 0.92 M, we replace the concentrations in the equilibrium expression and we calculate [H⁺]:
![\frac{(0.016 M)[H^{+} ]}{(0.92M)}= 1.8 x 10^{-5}](https://tex.z-dn.net/?f=%5Cfrac%7B%280.016%20M%29%5BH%5E%7B%2B%7D%20%5D%7D%7B%280.92M%29%7D%3D%201.8%20x%2010%5E%7B-5%7D)
⇒[H⁺]= (1.8 x 10⁻⁵)(0.92 M)/(0.016 M)= 1.035 x 10⁻³ M
The mass in grams of nitric acid that is required to react with 454g C7H8 is 932.72 grams
calculation
find the moles of C7H8 used
moles = mass/molar mass
= 454 g/92 = 4.935 moles
balanced reacting equation
C7H8 +3 HNO3 = C7H5N3O6 +3 H20
by use of mole ratio between C7H8 to HNo3 which is 1:3 the moles of HNO3 =4.935 x3 = 14.805 moles
mass of HNo3 = moles x molar mass
= 14.805 x 63 = 932.72 grams
part B
the mass of C7H5N3o6 = 2045.5 grams
calculate the moles of C7H8
= 829 g/92 g/mol = 9.011 moles
by use of mole ratio between C7H8 to C7H5N3O6 which is 1:1 the moles of C7H5N3O6 is also = 9.011 moles
mass of C7H5N3O6 is therefore = moles x molar mass
=9.011 x227 = 2045.5 grams
Answer: The average valence electron energy (AVEE) of this element =
1014.2 KJ/ mol or 1.0142mJ/mol.
Explanation:
The average valence electron energy = (number of electrons in s subshell x Ionization energy of that subshell) + (number of electrons in p subshell x Ionization energy of that subshell) / total number of electrons in both subshells of the valence shells.
The 5A elements are non-metals like Nitrogen and Phosphorus with the metallic character increasing as you go down the group, So a new 5A element will have characteristics of its group with 5 valence electron in its outermost shell represented as ns2 np3
Therefore the average valence electron energy (AVEE) of this element will be calculated as
The average valence electron energy = (2 x 1370 kJ/mol + 3 x 777 kJ/mol.) / 5
2740+2331/ 5 =5071/5
=1014.2 KJ/ mol or 1.0142mJ/mol.
