[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)
.
Answer:
<h3>
moles of carbon dioxide=13.95mol</h3>
Explanation:
First wrie down the balance chemical reaction:
Combustion reaction: The reacion in which hydrocarbon is burnt in the presence of oxygen gas and it releases heat and this reaction exothermic because heat of cumbustion is negative.
eg. burning of methane
By using unitry method,
From the above balanced reaction it is clearly that,
from 1 mole of propane 3 moles of carbon dioxide is formed
there fore,
from 4.65 mole of propane 
moles of carbon dioxide will form
moles of carbon dioxide=13.95mol
Answer:
E. CH₄ < CH₃Cl < CH₃OH < RbCl
Explanation:
The molecule with the stronger intermolecular forces will have the higher boiling point.
The order of strength of intermolecular forces (strongest first) is
- Ion-Ion
- Hydrogen bonding
- Dipole-dipole
- London dispersion
RbCl is a compound of a metal and a nonmetal. It is an ionic compound, so it has the highest boiling point.
CH₃Cl has a C-Cl polar covalent bond. It has dipole-dipole forces, so it has the second lowest boiling point.
CH₃OH has an O-H bond. It has hydrogen bonding, so it has the second highest boiling point.
CH₄ has nonpolar covalent C-H bonds. It has only nonpolar bonds, so the only attractive forces are London dispersion forces. It has the lowest boiling point.
Thus, the order of increasing boiling points is
CH₄ < CH₃Cl < CH₃OH < RbCl
I will solve this question assuming the reaction equation look like this:
<span>MnO2 + 4 HCl ---> MnCl2 + Cl2 + 2 H2O.
</span>
For every one molecule of MnO2 used, there will be one molecule of Cl2 formed. If the molecular mass of MnO2 is 87g/mol and molecular mass of Cl2 is <span> 73.0 g/mol, the mass of MnO2 needed would be:
Cl mass/Cl molecular mass * MnO2 molecular mass=
25g/ (73g/mol) * (87g/mol) * 1/1= 29.8 grams</span>
