Energy changes of solution:

·        Add 5cm3 of water in a test tube and measure its temperature.

·        Add a heaped spatula of solute to the test tube of water.

·        Stir with a thermometer and record the temperature change.

·        Fill your observations in the table below

 

Solute

Temp start oC

Temp final oC

Temp Change oC

  
 

KCl

 

 

 

  

CaCl2

 

 

 

  

KNO3

 

 

 

  

 

Demonstration - Migration of ions:

 

a)     Copper (II) Sulphate:

  • Make up a 10% solution of gelatin by adding boiling water to gelatin. 

  • Add an equal volume of 1M copper (II) sulphate solution and stir.

  • Pour into a U tube leaving a few cm’s depth.

  • Cool in an ice bath until the gel has set.

  • Fill up with saturated potassium nitrate solution.

  • Place carbon electrodes and connect to a lab pack on 20V DC for 30 Minutes.

b)     Potassium Manganate (VII):

 

  

  • Cut a piece of filter paper, dampen it and place it on a microscope slide.

  • Place 1 crystal of potassium manganate (VII) in the middle.

  • Connect 2 crocodile clips and connect to a lab pack on 20V DC for 30 Mins.

Solution

Which electrode does colour go to

Which ion is responsible for colour

Charge on ion

Copper (II) sulphate

 

 

 

Potassium manganate (VII)