Experiment 13.1c, to measure the emf of some electrochemical cells, p365

Apparatus

3 100cm3 beakers     1M ZnSO4        1M CuSO4       Zn + Cu strips   2 wires

2 crocodile clips        voltmeter          filter-paper or string soaked in KNO3     emery paper

Procedure 1

1.     Half fill the beakers with 1M ZnSO4 and 1M CuSO4

2.     Clean the metal strips with e. paper

3.     Put the strips into solutions accordingly, connect the crocodile clips to wires and strips and to voltmeter (Zn goes to negative)

4.     E.m.f.=             .

 Procedure 2

1.     Fulfil a beakers with Mg²⁺salt

2.     Put metal strip to one and connect it to voltmeter (negative)

3.     Change the salt-bridge and connect the beaker with Cu to positive

4.     E.m.f=              .

5.     Connect Mg and Zn the same way (Mg is negative. E.m.f.=                   

Procedure 3

1.     Heat ZnSO4 to boil

2.     Connect again the Zn and Cu as before. E.m.f=              . Temp. effect =                        .

Procedure 4

1.     Poor 9/10 of the ZnSO4 away and replace with water

2.     Connect again the Zn and Cu as before. E.m.f=              . Conc.. effect =                        .