(Accuracy):
The pipette, burette and volumetric flask only have a percentage error of + or - 0.1%. This is a small error. That is why they are used in this experiment. Be sure to take precautions such as making sure that when you pour in the HCl or Ca(OH) you do not let it run down the sides because some will be left on the sides thus making an inaccuracy. As you can see above, the bold says10.0cm3 of your Ca(OH), when instead it should have been 25.0cm3. The reason for this is because there was not enough of the Ca(OH) to perform all the experiments. This is a limitation due to the fact that 25.0cm3 would have been a more accurate measure because 10.0cm3 may not be enough for a clear result.
AnalysisJ
Rough
Accurate 1
Accurate 2
Accurate 3
Final burette reading cm3
37.3
37.2
37.1
37.3
Initial burette reading cm3
0
0
0
0
Volume used cm3
37.3
37.2
37.1
37.3
Mean titre cm3
37.3
37.2
37.1
37.3
This is the final part to the investigation. In this part of the investigation I aim to determine the final concentration of the limewater solution. I will go through my calculation step by step and explain what I am doing along the way.
Starting off, lets look at what we have. The equation for the reaction is:
30/5230/35230/image001.gif"> Ca(OH)2(aq) + 2HCl(aq) CaCl(aq) + 2H2O(L).
For the Ca(OH) we are trying to find the concentration in mol g dm-3. However we have the volume (10.0cm3 is how much we
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er solution. This would change the colour of the solution to light orange which would change to pink by the end of the titration.
5. After that I will place the flask onto a white tile placed on a clamp stand. Then I will open the tap of the burette that is held in the clamp stand and let the acid neutralise the alkali.
6. By the end of titration the limewater solution turns pink which indicates that it has been neutralised.
7. I will repeat the experiment at least thrice to make it a fair test. Repeating the experiment will also ensure that the results that I get are accurate.
The reaction that takes place can be described with the help of this balanced equation:
Ca (OH)2 + 2HCl → CaCl2 + 2H2O
In order to get reliable results from the exper
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at the end point would be reached before the equivalence. Variable Control You need t ensure that you take your chemicals from the same batch so as not to get two different concentrations each time you test them. Temperature and pressure should have no effect on the reaction Organisation Set up the equipment as shown in the diagram below, ensuring that the burette valve is closed. Run de-ionised water through the burette and wash all of the equipment with it First of all dilute the hydrochloric acid using by adding slowly 25ml of 2.00moldm-3 HCl to 475ml of de-ionised water in the 500ml beaker Then, using a pipette, put 100ml of the HCl solution into the burette Put 50ml of limewater into a conical flask using the pipette then add 5 drops of methyl orange to the solution, this should turn the solution a pale orange Open the
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. molarity
1dm3 = 10x10x10cm3 = 1000cm3
10.96 ¸ 1000 x 0.125 = 0.00137 = 1.3 x 10 mol Concentration of limewater in mol dm3
2(Volume of acid cm3) x Molarity of acid = Volume of alkalai (cm3) x Molarity of alkalai
1000 1000
2 (10.96cm3 x 0.125) = 25cm3 x mo.Ca(OH)2
1000 1000 = 0.00274 Mol. Ca(OH)2 = 0.00274 x 1000 = 0.1096 mol dm3
25
0.1096 x 74.1(Molarmass) = 8.12gdm3 Evaluation
My practical experiment went quite well and I got a variety of results, which were suitable for the task given. My results show that I got two identical results and one just 1.1cm3 off. Which suggests that I have been accurate and precise during the experiment. By being accurate it came about by specific apparatus I used, which restricted errors. However during the experiment I came across an array o ......
