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Experiment to Investigate the Effect of Concentration on Rate of ...

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Experiment to Investigate the Effect of Concentration on Rate of Reaction

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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. 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 (±0.015)
2 Wires
2 Beakers (50mL)
9molL-1 H2SO4 (±1%)
1 Cylinder (25±0.1mL)
Cystosepiment with two holes
Method
1. Dilute the 9molL-1 H2SO4 by pouring 5mL sulfuric acid solution and 35 mL water in a beaker and stir. 2. Use two wires to connect the copper stripe and zinc stripe...

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