pre lab

Experiment 1 (week 2) The purpose of this experiment is to become familiar with the precision and accuracy of scientific glassware. I figured the smaller the glassware the more accurate the measurements would be. Which when we were preforming the experiment proved my theory. As the glassware got smaller the easier it was to get the accurate amount of water into the glassware. We went from a big flask to a small beaker to an even smaller pipette. We used a scale to get the appropriate weight of the water in the different beakers. To test this, we weighed multiple glassware and different sized glassware. Then we calculated the precision and accuracy using the precision and accuracy formulas. First we took a 125 mL Erlenmeyer Flask and weighed it empty. We recorded it (77.6 g), then we filled the flask with 100 mL of water. Recorded it (170.5 g). To get the weight of the water we subtracted the weight of the water in the flask and the weight of the flask empty. (170.5 g - 77.6 g = 92.89 g) We knew we had to get the volume of the water, to do this we had to use the formula (mass = volume x density) and we got (92.89 g). We then repeated the process two more times to have a total of three trials. We could then find the precision and accuracy. To do this we used the accuracy formulas to find the absolute error. Which is, absolute error = |your result - accepted value|. 7.11 = |92.89 -100|. We then had to find the % error, using the formula % error = |your result -accepted value|/100 x 100%. We got, 7.11% = |92.89 -100|/100 x 100%. You repeat this process for the 2nd and 3rd trial. To find the precision we had to find the absolute deviation, % deviation, and the average % deviation. Using the formula Absolute deviation = |measured value - mean|, we got .006 = |92.89 - 92.86|. To find the % deviation you use the formula % deviation = Absolute deviation / mean x 100%, We got .7% = .006/92.896 x 100%. Repeat for trial 2 and 3. Then you can find the Average %