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Aims
Aims
To determine the rate of a reaction using a continuous monitoring method
To determine the rate of a reaction using a continuous monitoring method
To determine the order of reaction with respect to a substance using a concentration–time graph
To determine the order of reaction with respect to a substance using a concentration–time graph
These videos & activities will support your laboratory work and help you with the analysis of your results
These videos & activities will support your laboratory work and help you with the analysis of your results
Equipment
Equipment
● 50 cm3 of 1.0 mol dm–3 aqueous propanone solution ● 50 cm3 of 1.0 mol dm–3 sulfuric acid ● 50 cm3 of 0.02 mol dm–3 iodine solution (in 0.2 mol dm–3 potassium iodide solution) ● 0.01 mol dm−3 sodium thiosulfate(VI) solution ● 20 cm3 of 1% starch solution/indicator ● sodium hydrogencarbonate ● 100 cm3 beaker ● conical flasks ● 10 cm3 graduated pipette ● pipette filler ● spatula ● stop clock
Things to consider CPAC 2a
Things to consider CPAC 2a
CPAC 2a - Correctly uses appropriate instrumentation, apparatus and materials to carry out investigative activities, experimental techniques and procedures with minimal assistance or prompting.
· Prepare apparatus for titration
1. Wash out burette with acid
2. Add acid to burette using a funnel at eye level with glasses on
3. Remove air bubbles from tap
4. Record initial burette level
5. Pipet 25cm3 alkali to a conical flask using a bulb pipette and safety filler
6. Use a white tile
7. Add four drops of indicator
· Carry out titrations:
1. Titrate the alkali against the acid solution swirling the flask and with good control over the tap
2. Achieve drop wise addition near the end point
Things to consider CPAC 4a
Things to consider CPAC 4a
CPAC 4a – Makes accurate observations relevant to the experimental or investigative procedure.
· Read the exact burette value to 0.05cm3
· Obtain 2-3 concordant results
· Read scales correctly on all pieces of apparatus (teacher to check one)
· Read from bottom of meniscus when using burette (teacher to check one)
· Use pipet so that bottom of meniscus is on line
· if outlier(s) are identified, further repeats are carried out
Procedure
Procedure
1. Mix 25 cm3 of 1 mol dm−3 aqueous propanone with 25 cm3 of 1 mol dm−3 sulfuric acid in a beaker.
2. Start the stop clock the moment you add 50 cm3 of 0.02 mol dm−3 iodine solution. Shake the beaker to mix well.
3. Using a pipette, withdraw a 10 cm3 sample of the mixture and transfer it to a conical flask.
4. Stop the reaction by adding a spatula measure of sodium hydrogencarbonate. Note the exact time at which the sodium hydrogencarbonate is added.
5. Titrate the remaining iodine present in the sample with 0.01 mol dm−3 sodium thiosulfate(VI) solution, using starch indicator. Copy the table from the analysis section to record your results.
6. Continue to withdraw 10 cm3 samples at suitable time intervals (approximately every 3 minutes) and treat them similarly. Always note the exact time at which the sodium hydrogencarbonate is added.
Read the Hazcards COSHH information for the chemicals used in the practical so that you are aware of how to keep yourself and others safe 54, 85A,95A,98A.
Read the Hazcards COSHH information for the chemicals used in the practical so that you are aware of how to keep yourself and others safe 54, 85A,95A,98A.
- WARNING! The product from the reaction, iodopropanone, is a lachrymator (strongly irritant to the eyes). The reaction mixture should be poured down a fume cupboard sink with plenty of running water immediately once each measurement is complete.
Use eye protection.
Sodium thiosulfate releases sulfur dioxide when it reacts. Ensure that the room is well-ventilated.
Propanone is an irritant and is highly flammable.
Sulfuric acid solution is an irritant.
Do not run this practical for more than 12 minutes in total.
Things to consider CPAC 3b
Things to consider CPAC 3b
CPAC 3b - Uses appropriate safety equipment and approaches to minimise risks with minimal prompting.
· Collects all eqpt at start to minimise walking around the lab once practical work
· Sets up work space in an organised fashion
· Keeps work space tidy and organised
· Wears safety goggles & lab coats throughout
· No spillages/deals with spillages appropriately with minimal fuss
· Keeps stoppers on bottles when not in use
· No / minimal prompts required re safe working
· No / minimal prompts required re safe use of equipment and chemicals
· Correct disposal of reaction mixture (reagents & products) at end of practical
· Area cleared away properly & cleaned down (if needed) for following students without prompting
Required Resources
Required Resources
Core Practical 13a - Student Sheet.docxConsult CLEAPSS Hazcards® 54, 85A,95A,98A. Perform a risk assessment using up-to-date information before this practical is carried out
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