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The known literature value of acid concentration does not fall within the range of uncertainty. For the first experiment, it can be seen that the percentage error is lesser than the percentage uncertainty. Therefore, the random errors predominate the experiment. Random error involves precision uncertainties inherent in the equipment and effects of changes in the surroundings. I en random error cool a De caused Dye ten nucleation AT surrounding temperature. As the room temperature of chemistry laboratory may vary with time, we cannot control it. This variation in temperature may affect the reading of thermometer thus lead to madman error.
In order to minimize this random error, we should conduct the experiment in a room with constant room temperature to eliminate the influence of surrounding environment. In addition, the measuring cylinder used might be contaminated. Thus the volume of the acid and base measured may not be exactly ml. As the volume of reactant may not be as same as the instruction given, the temperature of reactant mixture will be affected. As a result, the enthalpy change of the reaction has random error. Therefore, we must ensure that all the apparatus are being washed properly before starting the experiment.
For the second experiment, it can be seen that the percentage error is greater than the percentage uncertainty. Therefore, the systematic errors predominate the experiment. Those errors may consist of incorrect use of equipment or poor experimental procedure. Firstly, I may not keep all the controlled variables remain constant throughout the whole experiment. For instance, I am supposed to stir the mixture of reactants with a constant frequency throughout the whole process as it will affect the reaction rate. However, due to human error, it is impossible for me to stir it at a constant speed.
This will affect the consistency of the results because the experiment has not been conducted under the exact same condition. In order to eliminate this error, I should use a magnetic-stirring equipment to stir the reactants throughout the experiment to ensure that this controlled variable is fixed. Additionally, the precision may also affect the result of data recorded. In this experiment, we use a thermometer with the uncertainty of В??O. ICC, which is not precise enough. In order to get more precise reading of temperature, we could replace the existing thermometer to an electronic one that has smaller precision.
Hence we will be able to get more precise value of the temperature thus minimizes systematic error. Furthermore, the reading of the thermometer may not be accurate as the mercury bulb may contact the bottom of polystyrene cup. This is because there is too little reactant inside the polystyrene cup. Theoretically, we should measure the temperature of the mixture of reaction inside the cup, thus the mercury bulb of thermometer should be immersed in the reactant instead of contacting the bottom of the cup because such practice may introduce inaccuracy of the temperature recorded.
In order to avoid this limitation, we may use ml sodium hydroxide instead of only ml to ensure that the temperature being recorded is the real temperature of the reactant mixture. In this experiment, heat loss is a factor that we must take into consideration. This experiment Is an exothermic reaction, neat energy transfers Trot system to ten surroundings. The recorded temperature is not the true temperature due to heat loss. In order to prevent heat loss, we cover the cup by lid and put the polystyrene into a beaker. However, we are still not able to minimize the heat loss.
Hence, we may change the polystyrene cup to a vacuum one which the container itself does not absorb heat energy thus prevent heat loss. In conclusion, I carry out the experiment smoothly. However, the experimental value I get from the calculation is not as same as the literary value. This inconsistency is mainly due to systematic error I encountered during the experiment. After evaluating the process of the experiment, I am able to make some assumptions about the sources of error and come up with methods to improve the experimental procedure respectively.