The percent error of the calculated percent water and accepted value is 3.36%. The mean of the class data for percent water was 50.8% and the standard deviation was 0.0300. Compared to the class results, my percent water was lower, but very close to the mean. The standard deviation has a low number; hence the data are not as spread out from the mean. One source of error that contributed to this percent error was that the hydrate, MgSO_4, may have been heated too long. This is a random error because when the hydrate has been heated too long, some of it could have reacted with the molecules in the atmosphere. As a result, the magnesium that was part of the anhydrous salt could have reacted with oxygen, thus forming magnesium oxide and losing
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This was due to the drafts in room affect the electronic balance, thus this error would have thrown off the recorded masses of the hydrate between intervals of heating and cooling. For instance, the recorded final mass of the hydrate after heating for 20 minutes could have been off by 0.002 g since the electronic balance was fluctuating between 0.546 g to 0.544 g. As a result, the inaccurate final mass of the hydrate would have affected the calculated mass of the water in hydrate, hence affecting the calculated percent water to be lower than the accepted value since the recorded masses are also lower than the accepted values. In order to minimize the source of error of constant fluctuations when measuring on the electronic balance, the windows in the room could be closed to prevent drafts from affecting the balance. This is because an electronic balance has finite precision, so the draft contributes a little bit to the mass when weighing the hydrate in the crucible. Percent water of hydration was used for the error analysis, rather than the number of moles of water for each mole of salt because percent water is a more accurate since it records a greater number of significant figures. In the calculations, the number of moles of water for each mole of salt is rounded to the nearest integer in order to write the final formula of hydrate. As a result, the rounding would allow most of the class data to be the same, whereas percent water has a more accurate calculation of how much water in is the
This was due to the drafts in room affect the electronic balance, thus this error would have thrown off the recorded masses of the hydrate between intervals of heating and cooling. For instance, the recorded final mass of the hydrate after heating for 20 minutes could have been off by 0.002 g since the electronic balance was fluctuating between 0.546 g to 0.544 g. As a result, the inaccurate final mass of the hydrate would have affected the calculated mass of the water in hydrate, hence affecting the calculated percent water to be lower than the accepted value since the recorded masses are also lower than the accepted values. In order to minimize the source of error of constant fluctuations when measuring on the electronic balance, the windows in the room could be closed to prevent drafts from affecting the balance. This is because an electronic balance has finite precision, so the draft contributes a little bit to the mass when weighing the hydrate in the crucible. Percent water of hydration was used for the error analysis, rather than the number of moles of water for each mole of salt because percent water is a more accurate since it records a greater number of significant figures. In the calculations, the number of moles of water for each mole of salt is rounded to the nearest integer in order to write the final formula of hydrate. As a result, the rounding would allow most of the class data to be the same, whereas percent water has a more accurate calculation of how much water in is the