Electrolysis design internal assessment

Electrolysis design internal assessment

Introduction to experiment
Electrolysis is a method using a direct electric current to drive a non-spontaneous chemical reaction. It involves the stage in the separation of elements from naturally occurring sources such as ores.

In this experiment, methods to alter rate of electrolysis will be attempted to be discovered. Although many contributing factors could affect the rate of electrolysis which could include internal energy within the electrolyte or surrounding temperature, these factors are hard to be controlled and changed systematically. Voltage supplied to the electrodes however can be easily changed and adjusted. Thus this experiment will attempt to find the relationship between Voltage applied to the electrodes and the rate of electrolysis.

What is the relationship between Voltage supplied and rate of electrolysis?

Variables and definitions
The rate of electrolysis is defined as mass of Cations of the electrolyte produced at the cathode per unit of time.

Independent variable – Voltage supplied to the electrodes (V)

Dependent variable – Rate of Cation production in the cathode (gs-1)

Controlled variables:
Variable
Method of control
Reason to control
Electrolyte
Use Zinc Sulfate
Different electrolyte Cations have different reactivity rates. Rate of Cation production can alter. *See hypothesis for more info.
Concentration of Electrolyte
1moldm-3 Zinc Sulfate
A highly concentrated substance can undergo electrolysis easier *see hypothesis
Amount of charge supplied
Maintain 2.1Amps (standard current in HK DC plugs)
Ohm’s law suggests V=IR, a current with an non-constant value could affect the voltage supplied

Variable
Method to Control
Reason to control
Direction of current

Positive to negative DC Current

An AC current will constantly switch the polarity of the electrodes

Time Allowed

Time 60 seconds

Different timing will affect the rate of Cations produced
Mass of Electrode
Only use 30g