Question

Please help ill give medals and become a fan!!!!!!!!!!!!!!

Answer 1

18
If the solubility of a gas is 7.5 g/L at 404 kPa pressure, what is the solubility of the gas when the pressure is 202 kPa? Show your work. (3 points)


19
Explain on a particle basis how the addition of a solute affects the boiling point, the freezing point, and the vapor pressure of the solvent. (6 points)


20
Calculate the hydrogen-ion concentration [H+] for the aqueous solution in which [OH–] is 1 x 10–11 mol/L. Is this solution acididc, basic, or neutral? Show your work. (3 points)


21
Calculate the acid dissociation constant of a weak monoprotic acid if a 0.5M solution of this acid gives a hydrogen-ion concentration of 0.000 1M? Show your work.
Hint: Monoprotic means containing one proton. (3 points)


22
Compare and contrast the properties of acids and bases. Include two similarities and two differences. (4 points)

Answer 2

18:
It's just like a proportion 7.5 . x

404 202

you multiply 7.5 by 202 = 1551

then you divide 1551 by 404 and you get 3.75

so your answer is 3.75g/L
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19:
A solute adds particles to a solution, such as:

NaCl-> Na+ + Cl- This puts 2 particles in the solution for every 1 formula unit of table salt. Any particle that gets added to a liquid interferes with the liquids ability to form crystals (ice), it interferes with the liquids ability to break surface tension ( boiling), and since less liquid molecules can escape there is less vapor pressure.

Addition of a solute means:

To freeze the solution you would have to slow the molecules down more than normal to encourage crystal growth, so the temp must be lowered.

To boil the solution you would have to speed the molecules up more than normal to encourage the molecules to leave the liquid, so the temp must be increased.

To increase the vapor pressure of the solvent has the same explanation as boiling.
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20:
Because [H+][OH-]= Kw = 1.0 x 10^-14

[H+]= Kw/ [OH-]= 1.0x 10^-14 / 1 x 10^-11 =1 x 10^-3 mol/L

pH = - log [H+]= - log 1 x 10^-3 = 3 < 7
the solution is acidic
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21:Your acid has the formula HA
Which undergoes HA<=> H+ + A-
ka = [H][A] / [HA]
you know [H+], but what are the others?
Write the electroneutrality equation for the entire reaction (including water's dissociation)
[H+] = [OH-] + [A-] ....we know that [H]>>>[OH], so
[H+] = [A-]
next write the total concentration equation (mass balance equation)
Ct = 0.5M = [A-] + [HA]
[HA] = 0.5 - [A-] = 0.5 - [H+]

all together you have:
ka = [H]^2 / (0.5 - [H+])
ka = 0.0001*0.0001/(0.5-0.0001) = 2.00x10^-8

Hope you can understand this approach
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22:Properties of acids include the following:

* React with most metals to form hydrogen gas
* Taste sour (like lemons)
* Frequently feel "sticky"
* Usually gases or liquids

Properties of bases include:

* Feel "slippery". (FYI: The slippery feeling is caused because your skin dissolves a little when you touch them.)
* Taste bitter (like baking soda)
* React with oils and greases (that's why they're used as drain and window cleaners)
* Frequently solids (though ammonia is a gas that's usually dissolved in water)

Answer 3

I hope I not only helped, but that you learned something to!! Good luck! :)

Answer 4

Thank you, ever time my teacher explains it I dont understand but now I do

Answer 5

I totally get the feeling, xD