top-rated free essay

Electroloysis of Water: Determination of the Fundamental Electronic Charge

By therookie24 Oct 21, 2012 730 Words


The fundamental electronic charge of water will be determined.

A system of collecting the formation of H2 and O2 using two inverted glass collections tubes and a 1-L beaker filled with water will be setup. An electrolyte (H2SO4) will be added to water to make it an electrical conductor. A small amount of electricity will be applied to the water (roughly 400 mA) to oxidize the oxygen and reduce the hydrogen at the same time. The molecular hydrogen and oxygen gases produced will be trapped in the separated, inverted tubes so that their volumes can be measured.

In comparing the volume of gases produced, applying Dalton’s Law and the Ideal Gas Equation along with the application of the stoichiometric ratio between the electron and the gases, the fundamental electronic charge will be determined.


H+ ions will join together at the cathode (the negative electrode) to produce H Atoms, and the H atoms will join to form molecules of H2 gas. At the positive electrode (the anode), H20 molecules will decompose to replace the H+ ions lost and release O2 gas. The reactions appear below.

2H+(aq) + 2e- ---> H2(g) Reduction (at the cathode) 2H20(l) ---> 4H+(aq) + O2(g) + 4e-Oxidation (at the anode)

The volume of H2 and O2 will be directly proportional to the time and current applied to the system. This will provide the number of electrons consumed on a stoichiometric ratio as follows:

1 H2(g) to 2 e-Reduction (at the cathode)(1)
1 O2(g) to 4 e-Oxidation (at the anode)(2)

The moles of electrons can be expressed as a rearrangement of the Ideal Gas Equation: Ne = PV/RT(3)

Where P = pressure in atm, V = volume in L, R = Gas Constant of 0.08206 atm mol-1 K-1 and T = temperature in Kelvin

The actual electronic charge of water will be calculated as follows:
e- = it/NeNx the stoichiometric ratio (1) or (2) above

Where i = current in amps, t = time in seconds, Ne = moles of electrons passing through the circuit from equation (3) and N = Avogadro’s number. The actual electronic charge will be compared to the theoretical charge of 1.603x10-19 Coulombs.

1. Convert height of the solution into mm Hg to get the hydrostatic pressure (pressure due to the liquid left in the gas collection tube): height of solution x density of solution
density of mercury

2. atmospheric pressure in the room – hydrostatic pressure = Ptotal (total pressure exerted by the gas trapped in the gas collection tubes)

3. a)Ptotal (total pressure) = PH2 + PH20or Ptotal = PO2 + PH20
b) PH2 = Ptotal - PH20

c)PH2 / 760 = Patm (Pressure)

4. Ne = PV/RT

5. e- = it/NeNx the stoichiometric ratio

| | Run 1| Run1| | Run 2| Run 2|
| | - (cathode)| + (anode)| | - (cathode)| + (anode)| | | Tube 2| Tube 1| | Tube 2| Tube 1|
| | H2| O2| | H2| O2|
Run Time in seconds|  | 987.13| 987.13| | 1102.82| 1102.82| Average Current|  | 0.303| 0.303| | 0.277| A|
Height of Solution| Hsol mm| 400.0 | 325.0 | | 81.5 | 314.2 | Volume of gas produced| Vgas (mL)| 40.10 | 19.72 | | 40.10 | 19.80 |  | Vgas (L)| 0.04010 | 0.01972 | | 0.04010 | 0.01980 | Temperature of solution| C| 24.0 | 24.0 | | 25.6 | 25.6 |  | Kelvin| 297.15 | 297.15 | | 298.75 | 298.75 | Vapour pressure of water | mm Hg| 22.377 | 22.377 | | 24.617 | 24.617 | Atmospheric pressure| Patm mm Hg| 770.50 | 770.50 | | 770.50 | 770.50 |  | Patm| 0.94567 | 0.95293 | | 0.97354 | 0.95103 | hhg hydrostatic pressure (mm Hg)|  | 29.41 | 23.90 | | 5.99 | 23.10 | Ptotal (mm Hg) in the tube|  | 741.09 | 746.60 | | 764.51 | 747.40 | PH2 (mm Hg)|  | 718.71 |  | | 739.89 |  |

PO2 (mm Hg)|  |  | 724.23 | |  | 722.78 |
| | | | | | |
moles gas n (rearranged Ideal Gas Equation) Ne = PV/RT| 0.001555 | 0.0007707 | | 0.001592 | 0.0007681 | e- = it/NeN|  | 3.194E-19| 6.445E-19| | 3.185E-19| 6.604E-19| stoichiometric ratio| Final| 1.597E-19| 1.611E-19| | 1.593E-19| 1.651E-19| | theoretical| 1.603E-19| 1.603E-19| | 1.603E-19| 1.603E-19| | Difference| -6.193E-22| 8.166E-22| | -1.028E-21| 4.801E-21| | % Error| -0.4%| 0.5%| | -0.6%| 3.0%|

Cite This Document

Related Documents

  • water

    ...Water is a chemical compound with the chemical formula H 2O. A water molecule contains one oxygen and two hydrogen atoms that are connected by covalent bonds. Water is a liquid at standard ambient temperature and pressure, but it often co-exists on Earth with its solid state, ice, and gaseous state, steam (water vapor). Water covers 71% of ...

    Read More
  • Determination of Quinine in Tonic Water

    ...Experiment 2 Title: Determination of Quinine in Tonic Water Objective: To Determine the Concentration of Quinine Hydrochloride in Sample (Schweppers) given, by plotting a Calibration Curve of Fluorescent Intensity against Concentration of Quinine Hydrochloride in ppm, after Fluorescence Intensity of a series of Standard Solution prep...

    Read More
  • Determination of Chlorine and Iodine in Water

    ...Determination of Chlorine and Iodine in Water I. Introduction The purpose of this laboratory was to determine the amount of chlorine and iodine in a sample of water by titration using a starch indicator and to standardize a sodium thiosulfate solution. Chlorine is added to municipal water supplies to purify it enough to become safe to drin...

    Read More
  • Determination of Hardness of Water

    ...Abstract Water “hardness” was analyzed in this experiment, through the determination of CaCO3 concentration. This was achieved by the titration of an unknown solution using a standardized 0.1M EDTA, and addition of Eriochrome Black T to the unknown, to indicate the endpoint of the titration. The average concentration of CaCO3 ...

    Read More
  • Determination of Water in a Hydrate

    ...Determination of Water in a Hydrate DESIGN – Aspect 1: Defining the problem & selecting variables Research Question: What percentage of Copper Sulfate Hydrate is water? Background Information: There are many ionic compounds that contain one or more waters of hydration in their formulae. They exists either in anhydrous or hy...

    Read More
  • Complexometric Determination of Water Hardness

    ...CHM152LL LAB MANUAL COMPLEXOMETRIC DETERMINATION OF WATER HARDNESS Complexometric Determination of Water Hardness Introduction Complex ions When a neutral molecule or anion (a Lewis base) donates electron pairs and attaches itself to a metal ion center (a Lewis acid), the resulting cluster, or complex, of atoms becomes a single complex i...

    Read More
  • Complexometric Determination of Water Hardness

    ...ABSTRACT The average concentration of CaCO3 obtained was 212 ppm, with a standard deviation of 1 ppt. The results indicate that the unk B tap water can be considered as hard water. INTRODUCTION Hard water is due to metal ions (minerals) that are dissolved in the ground water. These minerals include Ca 2+, Mg2+, Fe3+, SO42-, HCO3-. When...

    Read More
  • Samsung Electronics

    ...Samsung Electronics From Wikipedia, the free encyclopedia Samsung Electronics Co., Ltd 삼성전자 三星電子 Type Public Traded as KRX: 005930, KRX:005935, LSE: SMSN,LSE: SMSD Industry Consumer electronics Telecoms equipment Semiconductors Home appliances Founded 1969 (Samsung Electric Industries) 1988 (Samsung Elec...

    Read More

Discover the Best Free Essays on StudyMode

Conquer writer's block once and for all.

High Quality Essays

Our library contains thousands of carefully selected free research papers and essays.

Popular Topics

No matter the topic you're researching, chances are we have it covered.