The purpose of this lab was to determine the percent water in magnesium sulfate heptahydrate, or Epsom salt. The experimental percent water is determined to be 42.06% in both trials, making the average also 42.06%. To determine this percent water a heating and cooling procedure was used. First, the vials were cleaned of impurities using the lab oven and were not touched after this point. The 2 vials were then weighed and vial 1 weighed 14.7681 grams and the second vial weighed 14.7451 grams. Next 1.1075 grams of the hydrate was added into vial one and 1.1015 grams was placed into vial 2. The vials were then placed back into the oven with a starting weight of 15.8756 for the first vial and 15.8466 grams for vial 2. Once they were taken out of the oven and cooled they were weighed …show more content…
This heating and cooling was repeated until there was very little (less than 0.0010 grams) fluctuation in numbers. Vial one had a start weight of 14.7681 and an end weight of 15.4098, meaning the mass of the water was 0.4658. Vial 2 had a start weight of 14.7451 and an end weight of 15.3833, meaning the mass of the water in this sample was 0.4633. The mass of the water was found by subtracting the mass of the vial with the hydrate (the start weight) from the mass after the final heating (the final weight). To then find the percent water divide the water mass by the hydrate mass and multiply by 100 since the number is a percent. The water percent is determined to be 42.06%. To find a percent error, a theoretical percent water must be used. To find the theoretical percent error divide the mass of water by the mass of magnesium sulfate heptahydrate and multiply by 100 to get a percent. The theoretical percent water is