Essay

Unit 13A - : Investigate acid-base equilibria in order to understand buffer action and to optimise acid-base titration procedures

124 views 2 purchases

Course
Unit 13 - Applications of Inorganic Chemistry

Institution
PEARSON (PEARSON)

This is my Unit 13A assignment. I spent lots of time and effort on this and have achieved a DISTNICTION from this. If you have any questions, enquires or need some assistance please feel free to send me a message. Good luck with your assignment! If you could also just leave me a review that would h...

[Show more]

Preview 3 out of 19 pages

View example

Uploaded on March 23, 2023
Number of pages 19
Written in 2021/2022
Type Essay
Professor(s) Unknown
Grade A+

btec
applied science
chemistry
science
unit 13
useful

Study Level
BTEC
Examinator
PEARSON (PEARSON)
Subject
Applied Science 2016 NQF
Unit
Unit 13 - Applications of Inorganic Chemistry

darkabz

Member since 2 year 32 documents sold

CA$16.43

Added

Add to cart

Add to wishlist

100% satisfaction guarantee
Immediately available after payment
Both online and in PDF
No strings attached

Unit 13A: Application of Inorganic Chemistry
Half-titrations (Task 2)

Equipment
 50ml burette
 25ml volumetric pipette
 0.1M of sodium hydroxide
 A burette stand
 Funnel
 pH probe
 250ml beaker
 Ethanoic acid
 Buffer solution
Method
1. First, carefully make sure the 50ml burette is clamped safely into the burette sand and
make sure to fill the 50ml burette with the sodium hydroxide, with the bottom of the
meniscus touching directly on the line that states zero. Turn the tap on to let the air bubbles
out and then re-fill back to the line.

2. Then, using the 25ml volumetric pipette fill it with the ethanoic acid until it reaches the
line that will engraved faintly into the pipette.

3. After that, pour the 25ml of ethanoic acid into the 250ml beaker, the beaker should be at
a 45° angle and the pipette held vertically.

4. Once that is done, place the beaker directly under the bottom of the burette and have a
pH probe inside it.

5. Start the tap and pour 1cm³ of sodium hydroxide into the beaker, swirl it and check the
pH that is stated on the pH probe.

6. Record the value down into a table and continue until 15cm³ of sodium hydroxide has
been poured in. Continue by pouring 0.5cm³ of sodium hydroxide and recording the value of
the pH that is being stated.

7. Keep repeating this until the pH reaches approximately 12.

8. Once you have done a rough run, you can repeat the experiment two more times to get
an average. If the results are not concordant make sure to do an additional one to make sure
that they become concordant.

9. Once the additional runs have been done and averages worked out, make sure to plot
your data into a table and work out the half-equivalence point. The pH that is read will then
be equal to pKa.

Health and safety
As you will be working with acids and bases, you will need to ensure that the correct PPE is worn
such as: gloves, a lab coat and goggles. These will be used to reduce the chance of any irritation
that may occur if the substances end up getting onto the individual’s skin or eyes.

,The lab coat will be used to make sure that the any substances do not end up getting onto the
clothes of anyone and to protect everyone from any chemical spillages.
NaOH 1 2 3 Mean
0 2.95 2.95 2.95 2.95 The gloves will be used to protect anyone’s hands as
1 3.27 3.27 3.28 3.275 they will be using the chemicals and if the substances
2 3.51 3.51 3.52 3.515 do end up spilling onto their hands, they will be
3 3.70 3.70 3.70 3.70 protected, and it is very unlikely any form of irritation
4 3.85 3.85 3.85 3.85 will come to them. If the chemicals do spill onto the
5 3.97 3.97 3.98 3.975 person’s skin for any reason, make sure that they
6 4.07 4.07 4.06 4.065 inform the practical lead immediately and run their
7 4.15 4.15 4.15 4.15 hand under the tap for at least 2-3 minutes.
8 4.24 4.24 4.25 4.245
The goggles are used to protect the person’s eyes from
9 4.34 4.34 4.35 4.345
the chemicals spillage and if any chemicals were to end
10 4.40 4.40 4.40 4.40
up in someone's eyes it could cause painful irritation,
11 4.45 4.45 4.45 4.45
but the chance of eye damage is low due to the
12 4.56 4.56 4.56 4.56
concentration of the acid and base being very low,
13 4.65 4.65 4.65 4.65
however, making sure goggles are worn is imperative to
14 4.70 4.70 4.70 4.70
ensure they stay as safe as possible. If the chemical gets
15 4.75 4.75 4.75 4.75 into their eyes, make sure the practical lead is informed
15.5 4.81 4.81 4.81 4.81 immediately and they will most likely use the eye
16 4.85 4.84 4.82 4.83 cleaning station to clean the eye/eyes out thoroughly to
16.5 4.88 4.88 4.87 4.875 make sure no further damage will come to them.
17 4.98 4.91 4.92 4.915
17.5 5.00 4.98 4.98 4.98 Result table
18 5.05 5.00 5.01 5.005
18.5 5.08 5.05 5.05 5.05
19 5.17 5.08 5.07 5.075
How to work out the half-equivalence point
19.5 5.22 5.17 5.17 5.17
1. First start of by drawing a tangent on the
20 5.36 5.22 5.23 5.225
points where the function changes its direction
20.5 5.45 5.36 5.36 5.36
These lines will need to be parallel.
21 5.64 5.45 5.42 5.43
21.5 5.79 5.48 5.48 5.48
2. Then, draw a line between the two parallel
22 6.00 5.64 5.64 5.64
lines and measure the distance between them in
22.5 6.01 5.79 5.78 5.785
cm.
23 6.02 6.00 6.00 6.00
23.5 6.20 6.01 6.01 6.01
3. We will half the measured distance of the
24 6.55 6.02 6.03 6.025
two parallel lines and draw a line from that point
24.5 7.35 6.20 6.21 6.205 directly to the point on the line of the points that
25 8.74 6.55 6.54 6.545 have been plotted.
25.5 9.40 7.35 7.35 7.35
26 10.10 8.74 8.75 8.745 4. Finally, you can read off the graph and
26.5 11.30 9.40 9.41 9.405 this will give you the volume of sodium hydroxide
27 11.38 10.10 10.10 10.10 solution that was poured in. Half this value and
27.5 11.59 11.30 11.30 11.30 read off the graph. This will give you the pH, which
28 11.67 11.38 11.39 11.385 is equal to the pKa, giving you the value of the pKa.
28.5 11.72 11.59 11.60 11.595
29 11.73 11.67 11.68 11.675 Graph
29.5 11.79 11.72 11.70 11.71
30 11.82 11.79 11.80 11.795
30.5 11.88 11.82 11.83 11.825
31 11.91 11.88 11.89 11.885
31.5 11.94 11.91 11.91 11.91
32 11.96 11.94 11.94 11.94
32.5 12.1 11.96 11.96 11.96
33 12.2 12.1 12.1 12.1

, Derivation

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying these notes from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller darkabz. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for CA$16.43. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

75323 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy study notes for 14 years now

Start selling

Essay

Unit 13A - : Investigate acid-base equilibria in order to understand buffer action and to optimise acid-base titration procedures

Document information

Subjects

Written for

Seller

Reviews received

Content preview