practicals

Question 1

how to recrystallise

Answer 1

cool, filter and leave to dry

Question 2

plan an experiment to measure enthalpy change of neutralisation

Answer 2

acid and alkali mixed
take temp at start and finish
q= m c 🔺T
energy scaled up to form 1 mol of water
enthalpy of neutralisation = - energy change

Question 3

How to prepare standard solution

Answer 3

Dissolve solid in water
Transfer to volumetric flask and rinse
Make up to 100 cm3
Invert flask
Details:
Use 3dp balance
Rinse beaker with distilled water and transfer washings to flask
Use dropping puppets when filling to mark
Stopper, invert several times to mix

Question 4

How to purify impure compound from 2 layers

Answer 4

Separating funnel
The bottom is the organic layer
Dry with calcium chloride
Distilled at 222 C