Home
Search
Gallery
Blogs
Dictionary
Textbooks
Resource Library
Flashcards
Latest Topics
Ask a Question
Home
Take a Tour
Study Tips
Help Pages
Contact Us
Gallery
Recently Added
Search
Blogs
Dictionary
Add New Word
Random Term
Recent Changes
Resource Library
Share Your Resources
Recently Added
Search
Ask a Question
Log In
Sign Up
homework help
portal
Q & A Board
Gallery
Notes and Downloads
This Board
Research Articles
Entire Website using Google
Forum
Search
Advanced Search
Image Gallery
Resource Library
Browse by
Textbooks
Chat
Subjects
Recent
Posts
•
Latest Topics
•
Unresolved Questions
Top Posters
Since Sunday
21
8
C
6
6
m
5
m
5
m
5
c
5
c
5
m
4
b
4
i
4
This topic contains 1 attachment.
Home
Q & A Board
Science-Related Homework Help
Chemistry
(Moderator:
Laser_3
)
Print
New Topic
Buffer Lab help+advice?
Annonn
Annonn
wrote...
Go to Answer
Posts:
116
Rep:
1
0
A month ago
A month ago
Buffer Lab help+advice?
1. Find the
Molar concentration of HC
2
H
3
O
2
(M)
-I'm not sure if each buffers affect the molar concentration, but I searched up the normal molar concentration for HC
2
H
3
O
2
and found that it is 0.8527 M. Can anyone confirm that or steer me in the right direction on how to solve for the molar concentration?
2. Using Excel, prepare two charts, each with two series, from your data.
Create a separate chart for your titrations using NaOH with a series plotting your
titration with Buffer A and a series plotting your titration with Buffer B.
Do the same with your titrations using HCl.
-I think I understand how to make the graphs: there will be 4 separate graphs, Buffer A - NaOH, Buffer A - HCl, Buffer B - NaOH & Buffer B - HCl. Please give me any advice if my thought process is on the right track.
3.
Write reaction equations to explain how your acetic acid-acetate buffer reacts with an acid and reacts with a base.
4.
Buffer capacity has a rather loose definition, yet it is an important property of buffers. A commonly seen definition of buffer capacity is: “The amount of H+ or OH– that can be neutralized before the pH changes to a significant degree.”
We will consider 2 pH units to be significant. Use your data and your charts to determine the buffer capacity of Buffer A and Buffer B.
-I don't expect anyone to do the work for me (especially for the graphs), just please give me advice on where to start, any formulas that may help, etc.
Read 165 times
9
Replies
Report
Replies
bio_man
wrote...
#1
Educator
A month ago
Report
Answer verified by a
subject expert
bio_man
bio_man
wrote...
#2
Answer Link
Educator
Top Poster
Posts:
31040
Rep:
3362
15
A month ago
A month ago
Sign in
or
Sign up
in seconds to unlock everything for free
Login with Facebook
Login with Google
Login with Twitter
See if this helps for question #4
Buffer A.
Moles of NaC2H3O2 (a base component of buffer) = 0.031 g/(82 g/mol) = 3.78*10-4 mol
Moles of HC2H3O2 (an acid component of buffer) = 0.1 mol/L * (100/1000) mL = 0.01 mol
Now, pH = pKa + Log([base]/[acid])
The buffer capacity range is (4.74-1) to (4.74+1) = 3.74 to 5.74
By the addition of acid, pH decreases, i.e. the max. pH for the buffer capacity = 3.74
i.e. 3.74 = 4.74 + Log{(3.78*10-4 - x)/(0.01+x)}
i.e. (3.78*10-4 - x)/(0.01+x) = 0.1
i.e. 3.78*10-4 - x = 0.001 + 0.1x
i.e. 1.1x = 6.22*10-4
i.e. The buffer capacity =
5.654*10-4 mol
Buffer B.
Moles of NaC2H3O2 (a base component of buffer) = 0.314 g/(82 g/mol) = 3.83*10-3 mol
Moles of HC2H3O2 (an acid component of buffer) = 1 mol/L * (100/1000) mL = 0.1 mol
Now, pH = pKa + Log([base]/[acid])
The buffer capacity range is (4.74-1) to (4.74+1) = 3.74 to 5.74
By the addition of acid, pH decreases, i.e. the max. pH for the buffer capacity = 3.74
i.e. 3.74 = 4.74 + Log{(3.83*10-3 - x)/(0.1+x)}
i.e. (3.83*10-3 - x)/(0.1+x) = 0.1
i.e. 3.83*10-3 - x = 0.01 + 0.1x
i.e. 1.1x = 6.17*10-3
i.e. The buffer capacity =
5.61*10-3 mol
This verified answer contains over 280 words.
1
Report
Related Topics
Does a different amount of salt (conjugate base to acid) used in buffer affect buffer capacity?
Solved
The primary role of the carbonic acid-bicarbonate buffer system is
If Charlie, instead of the ligase buffer, added BamHI buffer to the tube he left
Solved
The most important chemical buffer system in the blood is the carbonic acid—bicarbonate ion buffer ...
Solved
Phosphate buffer (Multiple Choice)
Giving advice can be problematic because:
The primary buffer in extracellular fluid (ECF) is the _______________ buffer system. Fill in the ...
Solved
What is the buffer range (for an effective 2.0 pH unit) for a benzoic acid/sodium benzoate buffer? ...
Show More
bio_man
wrote...
#3
Educator
A month ago
Also, I found a lab that contains many of the same elements as your question.
Attached file
Lab_7.docx.pdf
(68.57 KB)
You must
login or register
to gain access to this attachment.
Report
Annonn
wrote...
#4
A month ago
First of all, I'd like to thank you so much for helping me and finding a similar lab!!
I'd like to ask one more thing about finding the buffer capacity. So, as I was filling out my website I have to use in order to submit my work is asking extra questions that were not in my lab manual:
I did the calculations based on the advice you gave me and ended up with Buffer A= 4.72*10
-4
and Buffer B= 4.63*10
-3
. But I am not sure if those calculations would be for the NaOH or HCl treatment if that makes sense.
Report
bio_man
wrote...
#5
Educator
A month ago
@Annonn, what did you get for the molar concentration? I will need that to verify your answers
Report
Annonn
wrote...
#6
A month ago
Buffer A= 0.1 and Buffer B= 1.0
Report
bio_man
wrote...
#7
Educator
A month ago
Ok, let's assume your data looks like this:
The calculations would look like this:
I can provide you with another example if you like, but this should sum it up
Report
Annonn
wrote...
#8
A month ago
Thank you, that helps a lot!
Report
bio_man
wrote...
#9
Educator
A month ago
Will mark the topic solved for now 👍
Report
New Topic
Quick Reply
[center][color=gray]Please [b]login or register[/b] to leave a reply[/color][/center]
Explore
Post your homework questions and get free online help from our incredible volunteers
102 People Browsing
266 Signed Up Today
Start New Topic
Take the Tour
Study Tips
Topics Trending
New
Browse by Textbook
Related Images
3129
36
10
Your Opinion
Do you believe in global warming?
Completely
To a large extent
Needs more research
I'm skeptic
Entirely a myth
Votes: 320
Previous poll results:
Which country would you like to visit for its food?
Latest Blogs
"Trust the Science" ?
Nipping Common Gardening Mistakes in the Bud
Fastest mammal in the sea
Should government intelligence agencies be trusted?
Simulating the evolution of aggression
Ready to ask a question on
Biology Forums
?
Try it out
Most theories in criminology are either completely accepted or completely rejected.
–
Legal Studies
Theoretical competition assists in a variety of ways such as in disregarding variables that have ...
–
Legal Studies
Fish performing Backstroke.
–
General Biology
Make the case that criminologists need to focus more (or less) on theoretical integration. Explain why.
–
Legal Studies
The two ways in which theoretical integration occurs are sequential and __________.
–
Legal Studies
Haynie's (2001) elaborated theory incorporated social control theories along with the properties of ...
–
Legal Studies
Integrated theories always receive strong empirical support in criminology.
–
Legal Studies
Which of the following statements best characterizes the empirical support which has been found for ...
–
Legal Studies
A gas under an initial pressure of .60 ATM is compressed at a constant temperature from 27 L to thre
–
Chemistry
How does theoretical elaboration differ from theoretical integration?
–
Legal Studies
Loading...