Empirical Formula Lab

599 Words2 Pages

Observation: • Magnesium ribbon started to glow when it was heated strongly • There was a change in the colour of magnesium from silver to grayish white • When the lid was opened, white ashes (MgO) escaped from the crucible while heating Evaluation: The purpose of the lab was to determine the empirical formula of a compound (magnesium oxide). In order to calculate the empirical formula, the mass of each element in the compound was determined. Then, the number of moles of each element in the sample was calculated. Finally, the molar ratio of each element as the smallest whole number was expressed, yielding the compounds empirical formula. The expected empirical formula of Magnesium Oxide was a 1:1 ratio. An error may have occurred from a simple rounding mistake, or all of the Magnesium may not have burned off during the experiment. If any of the unreacted Magnesium was left in the crucible, the empirical formula would be inaccurate because all of the metal would not have been converted to Magnesium Oxide (the formula would not be 1:1). In the future, I would allow more time for the Magnesium to burn off, assuring accuracy throughout the experiment. …show more content…

In all of my five trials, I needed to open the lid to allow oxygen to enter the crucible and react with the hot magnesium ribbon to form magnesium oxide. In this process, some white ash (MgO) escaped due to the strong heat due to convectional currents. Thus, this affected the mass on the product side. • The instable values in electronic balance. This is due to the small changes in mass. The values are only significant with more decimal places, but cannot be shown on the electronic balance. As a result, the machine rounds off the values when they overreach the range of the

Open Document