Answer:
1.35 moles of O²⁻
21.6 grams of O²⁻
Explanation:
We know that the charge on Aluminium ion is +3 (i.e. Al³⁺) while, the charge on Oxide ion is -2 (i.e. O²⁻). Therefore, the overall neutral Al₂O₃ compound has 2 Al³⁺ ions and 3 O²⁻ ions. Since, we can say that,
1 mole of Al₂O3 contains = 3 moles of O²⁻ ions
So,
0.450 moles of Al₂O₃ will have = X g of O²⁻
Solving for X,
X = 0.450 mol × 3 mol ÷ 1 mol
X = 1.35 moles of O²⁻
As the mass of an atom is mainly due to the presence of protons and neutrons hence, the addition of two electrons (-ve 2 shows two gained electron) to Oxygen will make a negligible change to the atomic masss of Oxygen because electron is said to be almost 1800 times lighter than proton. Hence, the ionic mass of O²⁻ will be 16 g/mol and the mass of given moles is calculated as,
Mass = Moles × Ionic Mass
Mass = 1.35 mol × 16 g/mol
Mass = 21.6 g
Answer: Option (b) is the correct answer.
Explanation:
Since energy of reactants is less than the energy of products. Therefore, it means energy is absorbed during the reaction.
As the energy required to break the bonds in the reactants is greater than the energy released when products are formed.
Therefore, it is an endothermic reaction.
Thus, we can conclude that the statement, it is endothermic because the energy required to break bonds in the reactants is greater than the energy released when the products are formed is correct.
Answer:
83%
Explanation:
2.4 moles of NO, 2.4 moles of O2, and 2.4 moles of H2O react to form 2.0 moles of HNO3. What is the percent yield of this reaction? ___ % 83.
Answer:
<u></u>
Explanation:
A <em>first order reaction</em> follows the law:
![rate=k[A]](https://tex.z-dn.net/?f=rate%3Dk%5BA%5D)
, where [A] is the concentraion of the reactant A.
Equivalently:
![\dfrac{d[A]}{dt}=-k[A]](https://tex.z-dn.net/?f=%5Cdfrac%7Bd%5BA%5D%7D%7Bdt%7D%3D-k%5BA%5D)
Integrating:
![\dfrac{d[A]}{[A]}=-kdt](https://tex.z-dn.net/?f=%5Cdfrac%7Bd%5BA%5D%7D%7B%5BA%5D%7D%3D-kdt)
![\ln \dfrac{[A]}{[A_o]}=-kt](https://tex.z-dn.net/?f=%5Cln%20%5Cdfrac%7B%5BA%5D%7D%7B%5BA_o%5D%7D%3D-kt)
Half-life means [A]/[A₀] = 1/2, t = t½:
That means that the half-life is constant.
The slope of the plot of ln [N₂O₅] is -k. Then k is equal to 6.40 × 10⁻⁴ min⁻¹.
Thus, you can calculate t½:
t½ = ln(2) / 6.40 × 10⁻⁴ min⁻¹
t½ = 1,083 min.
Rounding to 3 significant figures, that is 1,080 min.
Explanation:
The pKa value of acetic acid is determined experimentally by plotting pH titration curve.
The hydrogen ion, H+ concentration can be determined by performing a pH titration of a weak acid with a strong base like NaOH etc.
Starting from the dissociation equation for the acid,
HA(aq) + OH-(aq) --> H3O+(aq) + A−(aq)
we obtain for the point of half equivalence (where half of the acid has reacted with the base):
[A−] = [HA].
From the equilibrium equation
it therefore follows that
pKa = pH.
