• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

How duration affects the rate of electrolysis in a Voltaic Cell

Extracts from this document...

Introduction

Redox Design and Experiment Design and Conduct an experiment to investigate the effect of ONE FACTOR on redox reactions. Introduction:- The two main components of redox reactions are reduction and oxidation. Reduction is a gain in electrons and the decrease in oxidation number whereas oxidation is the loss of electrons and the increase in oxidation number. Voltaic cells, also known as galvanic cells generate their own electricity. The redox reaction in a Voltaic cell is a spontaneous reaction. For this reason, voltaic cells are commonly used as batteries. Voltaic cell reactions supply energy which is used to perform work. The energy is harnessed by situating the oxidation and reduction reactions in separate containers, joined by an apparatus (known as the salt bridge which primarily completes a circuit and maintains electrical neutrality) that allows electrons to flow. The functions of a voltaic cell are quite simple. There happens to be an anode and a cathode. The positive ions go the negative electrode (anode) whereas the negative ions go to the positive electrode (cathode). Electrons always flow from the anode (where oxidation takes place) to the cathode (where reduction takes place). Electrons flow across wires whereas ions flow across the electrolyte and the salt bridge. Aim:- The objective of this experiment is to see how the time affects the mass of the zinc electrode (anode) and the copper electrode (cathode) in a voltaic cell. Variables:- Variable Type of variable How it will be controlled Time (s) Independent (The one you change) ...read more.

Middle

In this case we use this formula because we know that the zinc is being oxidized to zinc 2+ leading the zinc electrode to corrode. This therefore results in a decrease in mass of the anode (zinc electrode). Thus, it would be better for us to use the formula 'Mass change = initial mass - final mass' so that it gives us a positive value for the mass change taking place at the anode. Mass change = initial mass - final mass = > 31.29 - 31.27 = > 0.02 Table 2 -Mass changes of anode and cathode for each time interval Time (�0.21s) Mass change of Anode (Zinc electrode)(�0.01g) Mass change of cathode (copper electrode) (�0.01g) 300.00 (5 minutes) 0.02 0.03 600.00 (10 minutes) 0.15 0.11 900.00 (15 minutes) 0.21 0.22 1200.00 (20 minutes) 0.29 0.37 1500.00 (25 minutes) 0.46 0.44 1800.00 (30 minutes) 0.68 0.75 2100.00 (35 minutes) 1.04 1.03 Graph 1:- Graph 2:- To derive the equation for the two separate reactions, the number of electrons gained or lost during the process has to be deduced. The mass change per minute can be deduced from the gradient. Therefore we first calculate the gradient of graph 1 (mass changes for zinc electrode). For calculating the gradient, find two points which perfectly fits in the grid. In this case, the points (0.04. 100) and (0.08, 200) Gradient= (Y2 - Y1) � (X2 - X1) = (0.08- 0.04) � (200 - 100) = (0.04) � (100) = 0.0004 Therefore, the gradient of the first graph is 0.0002. ...read more.

Conclusion

According to the graph in the previous page, there is a very strong positive correlation between the mass change and duration of electrolysis as can be deduced from the high R squared value. The change in mass over a certain period of time is very gradual because of the size of the electrons. Although a lot of electrons are able to flow through the electrolyte, there is not such a drastic change. By looking at the graph, almost all the error bars for the points touch the line of best fit which means the data is fairly accurate. The theoretical mass of a copper electrode would be 31.75g. From the results that have been tabulated, the mass of a copper electrode is 36.21g. The percentage error can be calculated using the following formula: Percentage error = difference x 100 theoretical value = 4.46 x 100 31.75 = 14.04% This shows that although there is not such a big difference between the theoretical value and the experimental value. Evaluation Limitation Type of error Improvement The mass of the anode was not measured therefore the rate of electron transfer between the two electrodes could not be determined. This could have increased or decreased the mass of the cathode. Random Measure the mass of the anode The power pack has internal resistance therefore not all the current was emitted. This could have decreased the current, thus decreasing the number of electrons produced. Random Use a resistor to accurately measure the current The top pan balance had a zero offset error. This could have increased the mass of the cathode. Systematic Use the top pan balance with the 0.001 uncertainty to obtain more accurate values. ?? ?? ?? ?? ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our International Baccalaureate Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related International Baccalaureate Chemistry essays

  1. Investigate the rate of reaction of luminol in various factors. The objective was to ...

    However, this will give inaccurate results, from the uncertainties of time and the colorimeter. To reduce the inaccuracy, time was measured instead. Before finding the rate equation, the data was plotted to identify the trend. Then the graphs would be modified to find the order of the reactions A.

  2. Investigating the effect of ion concentration in electrolytes on the potential difference in a ...

    Connect the two beakers of electrolyte by the salt bridge. 4. Place the two electrodes in their corresponding electrolytes - the iron electrode in the Iron (II) sulfate solution, and the copper electrode in the copper (II) sulfate solution.

  1. Enthalpy Change Design Lab (6/6)How does changing the initial temperature (19C, 25C, 35C, and ...

    or 1.00 mol dm-3 KOH(aq) so that the base of the temperature probe is touching the base of the 150 cm3 beaker. 9. The temperature readings of both Vernier LabQuest LoggerPro data collection units were monitored, and once one of the solutions of either 40.0 cm3 of 1.00 mol dm-3 KOH(aq)

  2. Electrochemical cells - investigate the effect of the temperature change of the anode electrolyte ...

    Salt bridge distance Don not move salt bridge in the experiment and make their distance is the same in each repeated experiments. UNCONTROLLED VARIABLES: (Factors you can't control but will at least monitor and how.) -Fluctuation of voltmeter, Systematic error of voltmeter can't be avoided -The mass of electrode, after

  1. IA-Enthalpy Change of Reaction - Zinc and Copper Sulphate.

    From the table, the initial temperature of 21.8 can be yielded. Step 2:Find t1 from table of values From the table of values, it can be seen that at 126 seconds, the temperature begins to rise; this is the t1 value.

  2. Electrolysis of copper sulphate

    Also, sparks could cause a fire therefore care must be taken nothing flammable is in the vicinity. Method 1. The Setup 1. Collect all required equipment. 2. Clean the 10 copper electrodes thoroughly using sandpaper to remove impurities that could inhibit electrolysis.

  1. Experiment to investigate the effect of concentration of electrolyte on the current of voltaic ...

    Minimize the position between the two stripes in order to maximize the current of the voltaic cell, but do not let them touch.

  2. Experiment Plan. Chemistry IA: Electrolysis of Metal Sulphate solutions (NiSO4)

    For this, a electronic balance will be used to weigh them. Controlled Variables Variable measured Method of measuring variable Controlled variables Temperature (°C) The entire experiment will be done in room temperature of around 24°C to ensure that the temperature for each trial will be the same.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work