Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: 777888 on December 07, 2004, 01:15:52 AM
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1)Calculate the % ionization of water (According to H2O<->H+ + OH-) at SATP.
I tried to calculate but I don't know how to calculate the % ionization...
1000g/x=18.02g/1mol
x=55.4939 mol H2O
[H2O]=55.4939mol/L
In pure water,
[H+]=1.0x10-7mol/L
[OH-]=1.0x10-7mol/L
...
2)Is H3PO3 a strong acid? If an acid is monoprotic or diprotic, what does it mean?
I hope someone can teach me! Thank you :)
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%=100x[H+]/[H2O]
Monoprotic acid split of one proton during dissociation, diprotic - two protons.
H3PO3 is diprotic because it real stucture id (HO)2PHO (one hydrogen atoms forms bond to P not to O) and is a weak acid.
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%=100x[H+]/{H2O]
Monoprotic acid spilt of one proton during dissociation, diprotic - two protons.
H3PO3 is diprotic because it real stucture id (HO)2PHO (one hydrogen atoms forms bond to P not to O) and is a weak acid.
Thank you!
% ionization:
=[H+]/[H2O]100%
=(1.0x10-7)/(55.4939)x100%
=1.8x10-7
But the answer is 10-5%
Is the answer wrong?
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3)What are two diagnostic tests that can distinguish a weak acid from a strong acid?
[litmus paper, pH meter, phenolphthalein, are they called diagnostic tests?]
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%=100x[H+]/[H2O] is incorrect if you put in any value for [H2O] other than 1. For solids and solvents the value in equlibrium equations are always taken as unit activity.
Therefore % = 100x[H+] = 10^-5
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%=100x[H+]/[H2O] is incorrect if you put in any value for [H2O] other than 1. For solids and solvents the value in equlibrium equations are always taken as unit activity.
Therefore % = 100x[H+] = 10^-5
Thanks
I thought that for every 55.4939 mol of H2O, 1.0x10-7 mol of H+ is produced. Why do you omit H2O?
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4.According to the table of acid-base indicators, what is the colour of litmus in a solution with a pH of 8.2, and methyl orange in a solution with a pH of 3.9?
Table of Acid-Base indicators:
Name Colour of HIn pH range Colour of In-
litmus red 6.0-8.0 blue
methyl orange red 3.1-4.4 yellow
I don't know how to use the table...what are the meanings of colour of HIn, pH range, and colour of In-? How can I predict the pH of the above problem?
5a)If alizarin yellow is added to a solution, and the colour of the solution turns red, what is the solution pH?
How can I predict the pH? Can someone teach me one? Thank you!
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%=100x[H+]/[H2O] is incorrect if you put in any value for [H2O] other than 1. For solids and solvents the value in equlibrium equations are always taken as unit activity.
Therefore % = 100x[H+] = 10^-5
Here we are talking about simple stoichiometry, not on equilibrium.
For very diluted solutions concentration and activity are equal.
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3)What are two diagnostic tests that can distinguish a weak acid from a strong acid?
[litmus paper, pH meter, phenolphthalein, are they called diagnostic tests?]
And also, does a strong acid have a lower pH than a weak acid?
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Here we are talking about simple stoichiometry, not on equilibrium.
For very diluted solutions concentration and activity are equal.
So is my answer correct???
% ionization:
=[H+]/[H2O]100%
=(1.0x10-7)/(55.4939)x100%
=1.8x10-7%
Thanks~
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4.According to the table of acid-base indicators, what is the colour of litmus in a solution with a pH of 8.2, and methyl orange in a solution with a pH of 3.9?
Table of Acid-Base indicators:
Name Colour of HIn pH range Colour of In-
litmus red 6.0-8.0 blue
methyl orange red 3.1-4.4 yellow
I don't know how to use the table...what are the meanings of colour of HIn, pH range, and colour of In-? How can I predict the pH of the above problem?
5a)If alizarin yellow is added to a solution, and the colour of the solution turns red, what is the solution pH?
How can I predict the pH? Can someone teach me one? Thank you!
Anyone knows how to predict the colour? :)
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4.According to the table of acid-base indicators, what is the colour of litmus in a solution with a pH of 8.2, and methyl orange in a solution with a pH of 3.9?
Table of Acid-Base indicators:
Name Colour of HIn pH range Colour of In-
litmus red 6.0-8.0 blue
methyl orange red 3.1-4.4 yellow
......
For question 4, I think that limus in a solution with pH 8.2 is blue. How about methyl orange in a solution with pH 3.9? (not red, not yellow)
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5a)If alizarin yellow is added to a solution, and the colour of the solution turns red, what is the solution pH?
......
How can I know the pH? There are many possibilities to make the indicator turns red, right?
PLEASE *delete me* I don't understand...
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1. What is the 'middle' color of the red ~ yellow?
2. What is the pH range of alizarin yellow?
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1. What is the 'middle' color of the red ~ yellow?
2. What is the pH range of alizarin yellow?
1. Orange I guess...
2. What is the meaning of pH range?
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1. right.
2.I mean the pH range of Colour of HIn and Colour of In-.
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pH range means the neutral colour?
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4.What is the colour of methyl orange in a solution with a pH of 3.9?
[THE ANSWER IS YELLOW, WHY? I don't get it at all!]
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Can someone teach me please? I am really confused.