How many particles would be found in a 1.224 g sample of K2O
2 answers:
Answer:
7.8286×10²¹ particles.
Explanation:
First we need to calculate the total molar mass of the compound, in this case:
Potassium (K) = 39.1 g/mol × 2 = 78.2 +
Oxigen (O) = 16 g/mol × 1 = <u> 16 </u>
Total(K₂O) = 94.2 g/mol
Then, we calculate the number of moles of the compound in the sample, this is done dividing de mass of the sample by the molar mass:
mol = 0.013 moles in our sample.
Finally, we calculate the total number of particles. The costant known as Avogadro number (6.022×10²³) is the number of particles or atoms contained in a mole of any substance. We need to multiply the number of moles by the Avogadro number.
particles = 0.013 mol × (6.022×10²³ particles/mol) = 7.8286×10²¹ particles.
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6) </span>A 0.12 M solution of an acid that ionizes only slightly in solution would be termed dilute and weak. You can determine it depending on its concentration. Such value as 0.12M usually defined as a dilute solution of a weak acid due to the fact that acid represents its <span>partial ionization which is a direct characteristic of a weak acid.
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9) </span>![[H+][OH-]= Kw = 1.0 * 10^-14](https://tex.z-dn.net/?f=%20%5BH%2B%5D%5BOH-%5D%3D%20Kw%20%3D%201.0%20%2A%2010%5E-14)
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Ct = 0.5M = [A-] + [HA]
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5) </span><span>The acid dissociation constant for an acid dissolved in water is equal to the equilibrium constant. I consider this option correct because we can obtan </span><span>Kw only when dealing with Kb, and we can conclude that the hydrolysis constant of the conujugate base.
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7) To solve this task we should appeal to H</span>enry's law that says<span> the solubility of a gaz is proportional to its partial pressure. And according to this we can understand that </span>202kPa is the half of 404kPa which means that the needed solubility must be divided by <span>2 7.5/2=3.75 g/L and that's all.
8) I think that the most important points which best show </span><span>how the addition of a solute affects the boiling point, the freezing
point, and the vapor pressure of the solvent are : BOILING: a</span>dditional attractive forces can only exist between solute and solvent and in order to boil they must be overcome for the solution;we should add KE to overcome the forces. FREEZING : to freeze we have to withdrawn KE as the solute particles are surrounded by solvent molecules. VAPOR : WHen <span>solvent shells are being formed the solute particles reduces the number of solvent particles that have sufficient KE to vaporize.</span>
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9) </span>
Since we got Ph of 3 in a result we can define solution as an acidic one, as I mentioned before.
10) Since the formula of the given acid is HA it undergoes like that :<span> HA<=> H+ + A- .
</span><span>ka = [H][A] / [HA].
Now we have only </span>[H+] and to go further you need to write <span>electroneutrality equation for the reaction :
</span>[H+] = [OH-] + [A-] (since [H]>>>[OH]), then
<span>[H+] = [A-]
</span>Then mass balance equation :
Ct = 0.5M = [A-] + [HA]
<span>[HA] = 0.5 - [A-] = 0.5 - [H+]
</span>Finally here is what we have done and get :
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- The common points of both acids and bases : <span>Hydrogen ions ,</span>
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