Experiment to investigate the effect of concentration of electrolyte on the current of voltaic cell

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Experiment to investigate the effect of concentration of electrolyte on the current of voltaic cell

Aim

The aim is to identify the relationship between the concentration of H2SO4 solution and the current of Cu-Zn voltaic cell.

Hypothesis

My hypothesis is that the greater the concentration of sulfuric acid the bigger the current of the voltaic cell.

In a voltaic cell, chemical energy is concerted to electrical though the oxidation and reduction happen on the electrodes. Current will not flow through pure water. There must be electrolytes dissolved in it before electricity can pass through it. When the concentration of sulfuric acid is increased, the number of ions is increased. There will be more ion carrying electric charge. Then, current is increased.

Introduction and Background

This is the Cu-Zn voltaic cell used in the experiment. Zinc has higher reactivity and it is more likely to loss electrons. Thus, electrons flow from Zn electrode to Cu electrode. Copper stripe is the positive electrode. Zinc stripe is the negative electrode.

Reaction happened on each terminal:

Positive terminal: Zn-2e-

Zn2+

Negative terminal: 2H

2e-

H2

It is assumed that bubbles (hydrogen gas) will come out from copper electrode.

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It is assumed that zinc and copper stripes are pure.

Classification of variables

Dependent variables

Current of the voltaic cell

Independent variables

Concentration of sulfuric acid solution

Controlled variables

Size of the copper and zinc stripes

Material of the electrodes

Distance between the electrodes during reaction

Volume and temperature of sulfuric acid solution

Materials and Apparatus

1cm

4cm Cupper stripes

1cm

4cm Zinc stripes

1 Ammeter (

)

2 Wires

2 Beakers (

)

9molL-1 H2SO4 (

1 Cylinder (25

mL)

Cystosepiment with two holes

Method

  1. Dilute the 9molL-1 H2SO4 by pouring 5mL sulfuric acid solution ...

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