100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
Previously searched by you
Previously searched by you
logo
APPLIED SCIENCE Unit 19: ASSIGNMENT A- DISTINCTION CA$17.41   Add to cart
Quickly navigate to
Preview
  2.  
  3. PEARSON (PEARSON)
  4.  
  5. Applied Science 2016 NQF
  6.  
  7. Unit 19 - Practical Chemical Analysis

Essay

APPLIED SCIENCE Unit 19: ASSIGNMENT A- DISTINCTION

5 reviews
 1669 views  21 purchases
  • Course
  • Unit 19 - Practical Chemical Analysis
  • Institution
  • PEARSON (PEARSON)

Unit 19: Practical Chemical Analysis A: Investigate quantitative analysis on the components of matrices to determine their composition BTEC/CTEC Level 3 Extended Diploma in Applied Science At Distinction grade level. With hand drawn graphs and with my OWN research (plagiarism-free). Please mess...

[Show more]

Preview 2 out of 8  pages

Document information

  • January 25, 2023
  • 8
  • 2022/2023
  • Essay
  • Unknown
  • A+

Subjects

  • applied science
  • unit 19a
  • unit 19
  • level 3
  • a investigate quantitative analysis on the components of matrices to determine their composition
  • btec level 3 extended diploma in applied science

Written for

  • BTEC
  • PEARSON (PEARSON)
  • Applied Science 2016 NQF
  • Unit 19 - Practical Chemical Analysis
All documents for this subject (29)

5  reviews

review-writer-avatar

By: chisomegu • 6 months ago

reply-writer-avatar

By: yeatrue • 6 months ago

Beg

review-writer-avatar

By: cliodhnafagan97 • 7 months ago

reply-writer-avatar

By: yeatrue • 7 months ago

I needed this

review-writer-avatar

By: alyasmin981 • 9 months ago

reply-writer-avatar

By: yeatrue • 9 months ago

Thank you!!

review-writer-avatar

By: fatimathebrainsurgeon • 1 year ago

review-writer-avatar

By: delviadominic2004 • 1 year ago

Seller

avatar-seller
yeatrue

Reviews received

Content preview

UNIT 19



Unit 19: Calculating the composition of matrices through quantitative analysis

Primary and secondary titrimetric standards:
Primary-
These are very unreactive in their pure forms which is useful compared to an unreliable reagent that
will easily react and change with its surroundings such as oxygen or H2O. Extremely reactive
chemicals cannot be properly used because of their instability as a standard. A standard should be
anhydrous meaning it doesn’t have any H2O bonded within its molecular formula. In addition, it
shouldn’t be too hygroscopic as it shouldn’t absorb water and it’s molecular weight should be high.
Secondary-
These are implicated within laboratories that produce materials for other labs for example, a
secondary standards and reagents. They use primary standards for primary calibrators or primary
reference materials. In a smaller lab however the secondary standard is used to calibrate control
material for analysing unknown concentrations of a drug. In summary, Secondary standard is
unusually used for external quality control in smaller labs and leads to standardisation of secondary
standards against primary standards first.

Percentage of copper in brass using Colorimetry
Equipment
1. Clamp
2. Stand
3. Pipette and filler
4. Wash bottles with distilled/de-ionised
water
5. Glass beakers
6. Burette
7. Balance
8. 250cm conical flask
9. 250cm Volumetric flask
10. Starch solution
11. Potassium iodide standard solution- Kl
(aq), 0.5 mol dm
12. Sodium thiosulfate- Na 20g, 0.1mol dm

Method
1. Dissolve 2.5g of brass in 10cm of strong
nitric acid.
2. Carefully transfer the obtained solution
to a 250cm graduated flask and add
0.5mol dm-3 sodium carbonate until the copper carbonate precipitate appears to signal
neutralisation
3. Add a few drops of 1 mol dm-3 ethanoic acid until the precipitate is entirely dissolved.
4. Titrate at least three times and increase the volume of the solution to 250cm3.
This is already given to us prepared by the lab, using the prepared solution we used the
method below to complete the experiment.
Second part- titration of thiosulfate:
1. Pipette 10ml of the Brass solution into a 100ml conical flask using a 10ml glass pipette.
2. Using a measuring cylinder, add 10ml of potassium iodide to the liquid, which will turn
brown.
3. Titrate with Sodium thiosulfate solution (in burette)

, UNIT 19


4. When the mixture has turned pale yellow, add 3-4 drops of 1% starch.
5. The mixture will take on a blue/black hue.
6. Continue titrating until the colour becomes nearly white.
7. Continue until you get two consistent results.
Precautions
1. When handling NO2, we should use a fume cupboard to prevent inhalation of nitrogen
dioxide fumes.
2. Gloves and goggles were used for extra safety measures
Results

Rough 1 2 3 4
Initial 0.00 7.30 20.00 29.50 0.00
volume/cm3

Final 7.30 20.00 29.50 45.20 13.00
volume/cm3
Titre/cm3 7.30 12.70 9.50 15.7 13.00
Average titre: 13.58

Calculations




Comparison
After comparing my results with a few of my classmates, I could see that our results are similar
meaning I had done the experiment correctly. Most of my classmates received received results that
had more than 50% of copper in the brass solution which shows that not many errors were made
that would create a vast change in results.

Evaluation
Brass is a copper and zinc alloy, with copper serving as the primary component.
Brass screws are composed primarily from 60-65 percent copper by mass. This process will have two
major stages: first, the reaction of brass with acid, followed by the reaction with KI and thiosulfate
titration.
By mixing copper iodine with the brass solution, iodine solution created will slowly turn brown and
as it is titrated, it turns pale yellow. A few drops of 1% of starch is added to change the solution from
pale yellow to dark blue/black. At the beginning, I had some trouble adding starch solution because I
added too much however I restarted and learnt from my mistake. This colour change demonstrates
the iodine bonding to the starch. After titration the residual iodine completely, the blue colour fades
away completely into a creamy white colour. Near the end of the experiment we transferred the

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

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

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

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 yeatrue. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for CA$17.41. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

77254 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
CA$17.41  21x  sold
  • (5)
  Add to cart