You can reduce the error by determining the indicator error (in a separate experiment) and subtracting that from the amount consumed during titration. It will improve your accuracy of experiment.
a) The balance error% seems a bit high. You can use a microbalance in calm and steady conditions (fan off, balance door closed and stable current supply etc.)
b) Use a burette of small volume capacity. It means if you are using a 100 cm^3 capacity burette and the volume required in one trial is estimated at 24 cm^3, you should use a burette of 25 cm^3 total volume.
c) Accuracy increases (error decreases) if reactants are used at lower concentration. it means small volume fluctuation will not affect the results too much..
Accuracy provides a correct reading of the measurement. If the experimental value differs from the actual value, the experimental value is inaccurate. If the experiment is repeated and gets an inconsistent result and is not accurate, this means that the results are inaccurate and imprecise to the actual value are the cause of the increase in percentage error. To reduce the percentage error, you’ll have to aim to get the actual value as close as possible and to do that you’ll need to repeat the experiment and get an experimental value close to the actual value to increase the accuracy and consistency of the results will decrease the percentage error.
However, there are several types of errors that need to be considered, such as systematic error and human error. In instances where something would relate to systematic errors is a burette reading with the combination of human error. The human error would be observing the results inaccurately and end up not having inconsistent results which also ends up as a systematic error because of the consistency reading of the burette. Below I’ve mentioned further errors and improvements.
Precision is mostly affected by random errors in the volume readings of the burette and pipette while accuracy is determined by the systematic error . Here are some of the ways to improve accuracy and precision for:
The glassware utilized which shown above is prone to instrument uncertainties and you can see that for each piece of equipment above used in my titration of khp and naoh. Like flask, burette, balance, and pipette.The instrument error is also called the tool error and is caused by the imperfection of the instrument used for the measurement. The instruments used in the analysis mainly refer to reference instruments like balances, glass measuring tools. Commercially available glass measuring tools like capacity bottles, pipettes, burettes, colorimetric tubes, etc., their true capacity is not all in line with their nominal capacity, for some of the more demanding analytical work, according to the allowable error range. The instrument used was tested for capacity.
Furthermore, to improve precision and accuracy and reduce instrumental error I need to do 4 things. Firstly increasing the number of trial in measurements as random errors can be minimized by increasing the number of steps mentioned above the dimensions are 2-4 times in the general work. Hence if there are no accidental mistakes, the results can be more accurate. Secondly I need to calibrate the balance and other equipment and make sure there is no damage or dents in the graduation and make sure the labels on the equipment are visible otherwise it will be classified as damaged hence resulting in giving incorrect readings which will give inaccurate results, therefore these need to be replaced. Thirdly the equipment I use needs to be used in the right environment with right conditions. The instruments need to be calibrated in an environment that resembles the one in which they will operate. If there are variations in the ambient environmental conditions occur, hence it will affect the calibration process. For example a buret if its calibrated in fluctuating temperatures it will be prone to temperature -induced errors when operated in a different environment. Fourthly I need to conduct a blank experiment which is a study based on the sample analysis procedure without adding the sample under the same operating conditions. A blank value is the value of the result obtained. In order to achieve a more accurate research result, blank values are subtracted from the sample result. The second is to take care of the calibration of the instrument. Cutting device failures attributable to instrument misalignment should be adjusted for correct volume and quality instruments such as desktops, pipettes, volumetric flasks, and analytical balance weight.
Also need to ensure that the balance is clean, each measurement contains only the chemical to be measured. If placed in a flask, the flask has to be dry and its weight is tared. The flask also has greater intervals between readings, we have to make sure that it is filled and read in the lower meniscus. I need to remember that the burette is read at the bottom of the meniscus. Two readings are needed, the before and after so how we read off values is important, we have to be consistent if the reading is in eye level and if the burette was filled up properly. I need to make sure that I fill the pipette well above the calibration line, making sure that no liquid gets into the pipet pump. We should also not try to remove the small amount of liquid remaining in the tip; this is because the pipets are already calibrated to retain this amount. Also take note that there should be no bubbles present for both the pipette and burette.
In addition the equipment which is utilized may not be as good. By this I mean as the uncertainty percentage is0.112 ± 0.012 moles/dm^3 that’s quantification of the doubt about the measurement result. Whenever possible we try to correct for any known errors of the equipment it can also be due to calibration error of equipment, hence all equipment needs to be calibrated. You may either reduce the sensitivity uncertainty by using higher resolution instruments (finer scale divisions) or increase the size of the measurement produced to decrease the apparatus uncertainties.In order to minimize the uncertainty in a reading of a burette, it is important to make the titre a bigger volume. This could be accomplished by: raising the volume and concentration of the substance in the conical flask or reduction of the concentration of the substance in the conical flask.
Also if we replace some equipment with better and more accurate and precise ones with less possibilities for errors.. For example, to replace a volumetric flask, you could use a graduated cylinder. Graduated cylinders are much smaller and measure out by a one number difference sometimes. There are a bunch of tick marks so you can get super exact measurements. Secondly to replace a balance, you could use an electronic balance. Instead of using the traditional weights of a balance, you could place the object on an electronic scale and it would report a value in grams, usually to the nearest 1000th place. Thirdly using sophisticated equipment like a ph meter to get a perfect endpoint because the human eye is not able to differentiate between pink and light pink.. This will affect the results giving inaccurate results. This is because we cannot overrun the titration by getting an exactly pink colour we need light pink colour that’s the correct endpoint. Hence the utilisation of a ph meter. Let me explain the theory behind it and explain why it’s really good and there’s less errors. The essential information to obtain is the equivalence point in an acid-base titration. If the number of moles of acid in the titration flask is given, the equivalence point is reached when the same number of moles of base from the desktop has been added. It is then possible to measure the base molarity, because the number of base moles added is the same as the number of acid moles in the flask and the amount of base added is also known. Similarly, if the number of acid moles in the titration flask is unknown, the equivalence point can be determined if the base molarity and the amount of base added are known.Sometimes, the solution’s pH can change drastically at the point of equivalence. By altering color over a given pH spectrum, an acid-base indicator works. There is also a drastic shift in the color of the indicator at the equivalence point if an indicator that changes color at the equivalence point is selected, since the pH changes so rapidly.An indicator is not essential in a potentiometric acid-base titration. To measure pH, a pH meter is used as the base is applied to an acid solution in small increments (called aliquots). A graph is then formed along the vertical axis with pH and the base volume applied along the horizontal axis. The equivalence point can be estimated from this graph and the molarity of the base can be measured. Therefore this potentiometric acid-base titration using a ph meter is more accurate and precise with less uncertainty .