• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9
  10. 10
    10
  11. 11
    11
  12. 12
    12
  13. 13
    13
  14. 14
    14

Investigation of the carbonate - bicarbonate system

Extracts from this document...

Introduction

INVESTIGATION OF THE CARBONATE - BICARBONATE SYSTEM (ALKALINITY OF AQUEOUS SYSTEMS) NAME: Leo Chiedu Aim Alkalinity in this experiment can be defined as the measure of the pH buffering capacity in water (e.g. river water, sea water, lakes etc.). This experiment was carried out using a prepared carbonate - bicarbonate solution against hydrochloric acid (0.1M HCl). Titration and pH indicator method was used to determine the equivalence point. The experiment also compares the titration and pH indicator method that is, looking at the option that will give a better approach in determining the equivalence point. Compared the digital and analogue pH meters that were used during the experiment by different groups. The experiment also aims at showing the importance of carbonate - bicarbonate system in environmental chemistry as it affects the natural water system. INTRODUCTION In Nigeria, water pollution is a serious environmental issue as it relates to the oil industries in the Niger Delta region, this can be attributed but not limited to the continuous flaring of fossil fuel. This creates acid rain deposition thus reducing the buffering capacity of rivers and lakes. The major source of living and earning in this area is fishing, but the continuous flaring of gas has resulted in acid precipitation, which has affected fishing. ...read more.

Middle

+ CO3-2(aq) Various results were obtained during the titration and pH indicator methods. Table (1) shows the values obtained when 0.1MHCl was titrated against the carbonate/bicarbonate mixture. Table (2) shows the values for the pH indicator method, table (3) shows the values for the derivative curve and table (4) shows the class result (raw data). The value obtained was then plotted on a graph to obtain various readings; the graphs would be explained later in the discussion. The plot on figure (1) shows the relationship between the pH and volume of 0.1M HCl used. Figure (2) is the derivative curve, figures (3 & 4) is used to determine the equivalence points of the reactions. Furthermore, figures (5 & 6) shows the 95% confidence intervals and standard error (S.E). Using titration method to determine the end points. Phenolphthalein indicator (cm3) Methyl orange indicator (cm3) 2.5 9.5 2.5 9.6 2.6 9.6 Table (1) volume of 0.1MHCl titrated against the carbonate/bicarbonate mixture Calculation (1) Determination of carbonates (CO3-2) levels using the titration and pH indicator methods, values obtained from the table (1) and the derivative curve. CO3-2 + 2HCl H2O + CO2 + 2Cl- (1.1) From the above equation; 1 mole carbonate (CO3-2) = 2 moles HCl step (1) 1 mole 0.1MHCl = 1x 10-4 mole HCl = 1/2 x 10-4 mole CO3-2 step (2) ...read more.

Conclusion

Methyl orange changes from yellow to but this change is not very clear to eye easily. Titration method involves carrying out the process repeatedly so as to get a concordant result, many factors can affect such reading, for instance, sample transfer to beakers will affect the quality of result obtained. However, the pH indicator method gives a more accurate and consistent result when used appropriately. This method gives a wider spread of values compared to titration method. Comparing class values. From the descriptive statistic, it can be seen that the mean values of both meters are not different, therefore, both meters are equal in performance. There is 95% confidence interval that the samples are probably from the source. Conclusion and Recommendation The alkalinity of the water sample was monitored using the titration and pH indicator methods for the determination of equivalence point. The end point value was used to determine the amount of carbonates and bicarbonates present in the water sample. Compared the class results to obtain a 95 % confidence interval that the sample was not from the same source. The following recommendation was made; > Further investigation should be carried out using a different methyl orange indicator, for instance, a mixed bromocresol methyl red indicator > Digital/automatic titrator should be used instead of the manual titration. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Aqueous 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 GCSE Aqueous Chemistry essays

  1. Marked by a teacher

    Thermometric Titration Investigation

    4 star(s)

    degrees C 1 ml = 1 g specific heat capacity Equipment Required This is a titration so the standard equipment is needed: * Burette (50 cm3) * Pipette (25 cm3) * Pipette filler * Burette stand * Beaker 100ml * Beaker 50ml But to Measure the temperature accurately I also need: * Polystyrene cup (Polypot)

  2. Peer reviewed

    An Investigation of Titration

    3 star(s)

    When I added the Methyl Orange to another sodium hydroxide, it went red for the acid but wasn't clear when neutralization had occurred. When I used Phenol Phtalein the substance turned purple when an alkali and went clear when neutralization took place.

  1. Investigating the effects of varying pH levels on the germination of cress seeds

    Using the second of the remaining two 100cm�measuring cylinders I then measured 20cm� of the 1% concentrated solution which I added to the bottle and shook gently to mix the solution. After all the solutions had been made, I used Universal Indicator to measure the pH value of all the

  2. Antacid Investigation.

    I shall do the following: Brush out the reminder of crushed tablet into the water. Instead of letting out 0.5 ml of HCl each time I shall let out 0.2 to make the experiment even more accurate. Spend more time reading the results.

  1. Freezing Point Depression

    for water is 0.51 calculate the boiling points for the NaCl and sucrose solutions evaluated. Molecular Mass Determination From Freezing Point Depression - Part 1 Using the 3 unknown solutions: 1. Take the first unknown and dissolve the amount stated on the label in 10 ml of water.

  2. Calibrating pH meters

    The goggles are made out of thick plastic which prevents any liquids entering the eye and causing any harm. Many people who wear contact lenses are under the illusion that there contact lenses will perform as eye protection not realising that the contact lenses are creating a risk of chemicals

  1. Aspirin Investigation

    Five drops of neutral Fe(III)Cl3 solution were added. A slight colour change was observed, the solution turning pale violet. This indicates that the sample contains a small quantity of salicylic acid and is not 100% pure aspirin. General Equation for FeCl3 Test + 2 OH OFeIII FeIII + + H+

  2. Reactivity Series Investigation

    From the graph I can see that calcium is the most reactive metal as the line graph goes up continuesly while the zinc,magnesium line in the graph stops at a point and doesn't rise after that.The magnesium stops reacting around about giving out 50cm3 of hydrogen gas and the zinc

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