[OH⁻] = 1.6 × 10⁻⁸ mol / dm³
<h3>Explanation</h3>
By definition, ![[\text{H}^{+}] = 10^{-\text{pH}}](https://tex.z-dn.net/?f=%5B%5Ctext%7BH%7D%5E%7B%2B%7D%5D%20%3D%2010%5E%7B-%5Ctext%7BpH%7D%7D)
, where ![[\text{H}^{+}]](https://tex.z-dn.net/?f=%5B%5Ctext%7BH%7D%5E%7B%2B%7D%5D)
is the concentration of proton in the solution.
pH = 6.2 for this solution. As a result, 
.
![[\text{H}^{+}] \cdot [\text{OH}^{-}] = \text{K}_w](https://tex.z-dn.net/?f=%5B%5Ctext%7BH%7D%5E%7B%2B%7D%5D%20%5Ccdot%20%5B%5Ctext%7BOH%7D%5E%7B-%7D%5D%20%3D%20%5Ctext%7BK%7D_w)
, where ![[\text{OH}^{-}]](https://tex.z-dn.net/?f=%5B%5Ctext%7BOH%7D%5E%7B-%7D%5D)
the concentration of hydroxide ions and 
is the dissociation constant of water.
at 0.10 MPa and 25 °C. As a result, ![[\text{OH}^{-}] = \text{K}_w / [\text{H}^{+}] = 10^{14} / (6.31 \times 10^{-7}) = 1.6 \times 10^{-8} \; \text{mol}\cdot \text{dm}^{-3}](https://tex.z-dn.net/?f=%5B%5Ctext%7BOH%7D%5E%7B-%7D%5D%20%3D%20%5Ctext%7BK%7D_w%20%2F%20%5B%5Ctext%7BH%7D%5E%7B%2B%7D%5D%20%3D%2010%5E%7B14%7D%20%2F%20%286.31%20%5Ctimes%2010%5E%7B-7%7D%29%20%3D%201.6%20%5Ctimes%2010%5E%7B-8%7D%20%5C%3B%20%5Ctext%7Bmol%7D%5Ccdot%20%5Ctext%7Bdm%7D%5E%7B-3%7D)
.
According to molecular orbital theory, atomic orbitals combine to form molecular orbital. Number of molecular orbitals are equal to number of atomic orbitals. Further, of the total number of molecular orbitals, half are called as bonding molecular orbital while remaining are anti-bonding molecular orbital. In case, if system contains lone pair of electrons, they occupy non-bonding molecular orbital. Highest occupied molecular energy levels are referred as HOMO, while lowest unoccupied molecular energy levels are referred as LUMO.
In case of B2 molecule, two B atoms combines to generate molecular orbitals. Attached is the MOT diagram of B2 molecule
From the attached figure, it is clearly evitable that high occupied energy level in B2 is π. Also, it must be noted both <span>pi molecular orbitals i.e. Pi 2Px and Pi 2Py at highest energy level (occupied).</span>
Answer: The enthalpy of the reaction is -109 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.
(1)
(2)
The final reaction is:
Subtracting (2) from (1):
Thus the enthalpy of the reaction is -109 kJ
Answer:
a. The original temperature of the gas is 2743K.
b. 20atm.
Explanation:
a. As a result of the gas laws, you can know that the temperature is inversely proportional to moles of a gas when pressure and volume remains constant. The equation could be:
T₁n₁ = T₂n₂
<em>Where T is absolute temperature and n amount of gas at 1, initial state and 2, final states.</em>
<em />
<em>Replacing with values of the problem:</em>
T₁n₁ = T₂n₂
X*7.1g = (X+300)*6.4g
7.1X = 6.4X + 1920
0.7X = 1920
X = 2743K
<h3>The original temperature of the gas is 2743K</h3><h3 />
b. Using general gas law:
PV = nRT
<em>Where P is pressure (Our unknown)</em>
<em>V is volume = 2.24L</em>
<em>n are moles of gas (7.1g / 35.45g/mol = 0.20 moles)</em>
R is gas constant = 0.082atmL/molK
And T is absolute temperature (2743K)
P*2.24L = 0.20mol*0.082atmL/molK*2743K
<h3>P = 20atm</h3>
<em />
Answer is: 8568.71 of baking soda.
Balanced chemical reaction: H₂SO₄ + 2NaHCO₃ → Na₂SO₄ + 2CO₂ + 2H₂O.
V(H₂SO₄) = 17 L; volume of the sulfuric acid.
c(H₂SO₄) = 3.0 M, molarity of sulfuric acid.
n(H₂SO₄) = V(H₂SO₄) · c(H₂SO₄).
n(H₂SO₄) = 17 L · 3 mol/L.
n(H₂SO₄) = 51 mol; amount of sulfuric acid.
From balanced chemical reaction: n(H₂SO₄) : n(NaHCO₃) = 1 :2.
n(NaHCO₃) = 2 · 51 mol.
n(NaHCO₃) = 102 mol, amount of baking soda.
m(NaHCO₃) = n(NaHCO₃) · M(NaHCO₃).
m(NaHCO₃) = 102 mol · 84.007 g/mol.
m(NaHCO₃) = 8568.714 g; mass of baking soda.
