Required practicals

Question 1

Method for making up a volumetric solution

Answer 1

1. Weigh the weighing oat before and after adding a solid to weigh by difference
2. Add the solid to a beaker
3. Add approx. 100 ml of distilled water to the beaker
4. Use a glass rod to stir the contents of the flask until the solid is dissolved in the water
5. Pour the solution into a 250ml volumetric flask through a funnel.
6. Include all rinsings
7. Add distilled water until the bottom of the meniscus touches the line
8. Put the stopper in and invert the flask

Question 2

Method for measurement of enthalpy change

Answer 2

1. Measure approx. 6g of hydrated copper sulphate
2. Add 25 cm3 of water into the polystyrene cup
3. Record the temp. of the water for three minutes (record every minute) and on the 4th minute add the copper sulphate.
4. Stir using the thermometer taking the temp every minute until its decreasing for 5 mins in a row
5. recording the readings in a table
6. To find the temp change plot a graph time against time
7. Compare at the 4 th minute by drawing a line for the 1st 3 points and a different line for the rest

Question 3

Method for an acid-base titration

Answer 3

1. Rinse a burette with ethanedioic acid (water will change the conc.)
2. Fill the burette with approx. 100cm3 of ethanedioic acid, ensuring to fill the jet space by opening the tap for a few seconds.
3. Use a pipette and pipette drawer to measure 25cm3 of NaOH until the meniscus is in line with the 25 marking
4. Remove the drawer over a conical flask to pour the contents in
5. Touch the end of the pipette against the NaOH in the conical flask to draw out remaining solution
6. Add2-3 drops of phenolphthalein indicator to NaOh, will turn pink.
7. Begin allowing small amounts of ethanedioic acid to the NaOH while swirling until it turns colourless
8. Repeat until you have 2 concordant results (+- 0.1)

Question 4

Method for investigation of rate of reaction

Answer 4

1. Add 10cm3 of sodium thiosulphate solution to 40cm3 of water in a conical flask, measure 5 cm3 of dilute HCl in a small measuring cylinder
2. Warm the thiosulphate solution in the flask to bring it to the necessary temp.
3. Put the conical flask over a piece of paper with a cross drawn on it.
4. Add the acid to it and start the clock
5. Swirl the flask to mix the solutions and place it on the paper with the cross. Take the initail temp of the mixture
6. Stop the clock when you can no longer see the cross through the solution and note the time taken. Record the final temp of the mixture.
7. Repeat 3 times
8. Plot a graph with ave temp against time

Question 5

Test for an alkene

Answer 5

1. Add approx. 1 ml of cyclohexene to a test tube, add an equal volume of bromine water and shake the contents vigorously
2. Record observations