Experiment 1: MEASUREMENT ert friday Bue /Pre-Lab Exercises 1. What is the length of the rod shown below? O 1 2 3 6 10 5 9 7 8 2. If Student A measures the volume of a liquid and reports its volume as 23.50 mL and Student B measures a different amount of the same liquid and reportS ts volume as 15.0 mL, is it likely that the students used the same measuring device? Yes or no? Explain your answer. 23 23-5O X ISO 72.0ML 3. If you were asked to measure 25.0 mL of a liquid and to transfer it to another container, which of the following glassware could you use? Choose all that apply. Give reason(s). D.mL will Leads to s approximetly Va) A 50-mL buret with smallest divisions of 0.1 mL-13Cu2 b) A 50 mL beaker with smallest divisions of 10 mL c) d) A 50-mL volumetric flask A 50-mL graduated cylinder with smallest divisions of 1 mL e) A 25-mL pipet 4. A group of five students attempted to estimate 100 g of a substance by balancing the amount of the substance with a 100-g standard mass and obtained the following masses after each estimated amount was weighed: 95.8634 g, 80.8125 g, 106.5078 g, 98.2865 g, and 86.4453 g. Create a data table as shown below and use the data to determine the answers to the following questions: Mass (g) % Deviation Deviation (g) Error (g) % Error a) What is the mean? And what is the true value? b) What are the deviation and % deviation from the mean for each value? c) What are the error and % error for each value? Post-Lab Questions 1. How many significant figures are in the cm measurement of Rod A? How did you figure out how many decimal places to use in your answer? 2. Why do you think that the beaker is 3. Could you use a 100-mL volumetric flask to deliver 50.0 mL of a liquid? Explain. Which measuring devices could you use to trans fer 50.0 mL of a liquid? Explain. 5. Chefs often estimate the amount of ingredients needed for a dish. Do you think it would be a good idea to estimate rather than weigh the amount of chemicals needed for an experiment? Explain. not stamped with either TD or TC? 4. What does the percent error in your masses tell you about the accuracy of estimating? 6. TC 30 Pre-Lab 2 TD