100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
Previously searched by you
Distinction - BTEC Applied Science Unit 2 LA A- Learning aim A: Undertake titration and colorimetry to determine the concentration of solutions.$11.69
Add to cart
Unit 2- Practical Scientific Procedures and Techniques
All documents for this subject (361)
Seller
Follow
pharm2003
Reviews received
Content preview
Unit 2 LA A Titrations name
Introduction:
In this experiment, I will undertake titration and colorimetry to determine the concentration of
solutions, making sure that all the equipment is calibrated and cleaned before and after
being used. I will prepare a standard solution, prepare standardisation of HCl, carry out
titration of sodium hydroxide with HCl (using Phenolphthalein indicator) and determine the
concentration of copper (II) sulphate solution by colorimetry. I will also have to calculate the
concentration of HCl after standardisation and NaOH after carrying out titration.
Prepare a standard solution and standardisation of Sodium Carbonate:
Equipment:
● Balance
● Funnel
● Distilled water
● Volumetric flask
● Sodium carbonate
● Weighing boat
● Solid sodium hydroxide
Method to prepare a standard solution:
1. Calibrate the weighing balance that will be used.
2. Place the weighing boat on the balance and press the Tare button so the display
shows 0.0000 grams (decimal places will depend on the balance).
3. Weigh the anhydrous sodium carbonate between 1.25 and 1.45g.
4. Gently transfer the sodium carbonate to a beaker, recording the measurements
accurately and precisely to establish the exact mass transferred.
5. Fill the beaker with 150 cm3 of distilled water then stir to completely dissolve the
sodium carbonate.
6. Carefully and precisely transfer all of the solution to a 250 cm3 volumetric flask and top
up with more distilled water to make the solution 250 cm3.
Method to prepare the standardisation of an acid (HCl):
1. Calibrate the pipette that is going to be used.
2. Pour 25 cm3 of sodium carbonate solution into a 250 cm3 conical flask, along with a
few drops of phenolphthalein indicator using a pipette.
3. Clean and fill a burette (50 ml) with a hydrochloric acid solution with a concentration
of around 0.1 M.
4. Add the hydrochloric acid to the sodium carbonate solution and titrate until the
indicator changes the colour of the solution.
1
, Unit 2 LA A Titrations name
5. Record all measurements accurately and precisely to calculate the exact amount of
hydrochloric acid needed to reach the titration’s end point.
6. Repeat the experiment 3 times to get more reliable results.
A.P1 Part
Risk assessment:
● Sodium hydroxide solution: they are highly corrosive, causing irritation of the eyes. To
prevent this, goggles and gloves must be worn to protect the eyes and the skin
respectively. If it goes in the eyes, for at least 20 minutes, immerse the eye in softly
running tap water. Seek advice from a doctor. If a trip to the hospital is essential, keep
washing the eye during the ambulance ride. If it is split on the skin or clothes, dispose
of any contaminated clothing (if possible). After that, soak the skin with a large
amount of water. Consult a doctor if a big area is affected or blistering occurs. If it is
split on the floor, stools, etch then wipe away small amounts with a moist towel and
thoroughly rinse. Cover with mineral absorbent (e.g., cat litter) and scoop into a
bucket for larger amounts, especially for (moderately) concentrated solutions. Citric
acid can be used to balance things out. Rinse well with water.
● Broken glassware can cause cuts in the skin, to prevent this, check the glassware
before their use, put the equipment in the middle of the table instead of the edge. If a
glassware was damaged before using them, replace it. The glassware should be
handled carefully and properly.
Results (calculation of moles in HCl):
Volumes in cm3 Rough 1st trial 2nd trial 3rd trial
Initial volume 0.00 0.00 0.00 0.00
Final volume 14.80 14.40 14.70 14.60
Volume of HCl used 14.80 14.40 14.70 14.60
Average volume of HCl used 14.57 14.57 14.57
Average volume used in cm3 = (14.40+14.70+14.60)/3 = 14.5666666667 cm3 = 14.57 cm3
Mass for Na2CO3= 23x2+12+16x3= 106
1.255g of Na2CO3 used so, number of moles= 1.255/106= 0.01183962264 moles in 250cm3
Equation for the reaction: Na₂CO₃ + 2HCl → 2NaCl + H₂O + CO₂
Moles of Na2CO3 in 25 cm3= 0.01183962264/10= 0.00118396226
2
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 pharm2003. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $11.69. You're not tied to anything after your purchase.
