Laboratory Techniques Lab Report PDF

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Laboratory Techniques Lab Report Option One: Density Measurements Virtual Lab Instructions: For this investigative phenomenon, you will need to determine the densities of an unknown solid and liquid using different methods of measurement to determine if the solid will float on water. Record your observations and test measurements in the lab report below. You will submit your completed report. Title: Density lab Livia goodman B. Bogardus 6/10/21 Objective(s): Determine the densities of an unknown solid and liquid using different methods of measurement to determine if the solid will float on water. Hypothesis: I think the solid would have a higher density than the liquid. Make a prediction about the densities of the unknown solid and liquid. How will mass affect the volume of the solid, and how will volume affect the mass of the liquid? Procedure: Access the virtual lab and complete Part I and Part II trials of the experiment. Because this lab is virtual, summarize the steps in which data were collected for the samples. In addition, list and explain your controlled variables, independent variable, and dependent variable for this lab. 1) Measure the mass of the empty cylinder 2) Add the liquid (aprox. 8.5 mL) 3) Measure the mass with the liquid (and the cylinder) 4) Complete 3 trials 5) Move on to the solid 6) Measure the mass of the solid 7) Add the liquid 8) Measure the volume 9) Drop the solid in the cylinder 10) Measure the volume with the solid 11) Complete 3 trials Materials: Laboratory Techniques Virtual Lab Variables:

Remember, controlled variables are factors that remain the same throughout the experiment. An independent (test) variable changes so that the experimenter can see the effect on other variables. The dependent (outcome) variable will change in response to the test variable. Controlled variables: The amount of water in the cylinder because it stayed the same throughout this experiment Independent variable: the weight of the cylinder and solid alone because this was able to be controlled Dependent variable: the solid in the water because this changed during the experiment Summary of Steps: Data: Type the results of your tests in the data table below. The saved results of your measurements can also be found by selecting the data table button within the virtual lab. Don’t forget to record measurements with the correct number of significant figures. Hint: Using the same instrument, you should have the same number of digits to the right of the decimal (all masses, then all volumes, etc.). Part I: Density of Unknown Liquid

Trial 1

Trial 2

Trial 3

Mass of empty 10 mL graduated cylinder (grams)

26

26.8

27

Volume of liquid (milliliters)

9

8.5

8.9

Mass of graduated cylinder and liquid (grams)

37.5

37.5

38.2

Part II: Density of Irregular-Shaped Solid

Trial 1

Trial 2

Trial 3

Mass of solid (grams)

42.093

41.902

39.217

Volume of water (milliliters)

40

49

51

Volume of water and solid (milliliters)

45

54

56

Calculations:

Show your calculations for each property. Be careful to follow significant figure rules in each calculation. Part I: Density of Unknown Liquid Calculate the mass of the liquid for each trial. (Subtract the mass of the empty graduated cylinder from the mass of the graduated cylinder with liquid.) Trial 1: 11.5 Trial 2: 10.7 Trial 3: 11.2 Calculate the density of the unknown liquid for each trial. (Divide the mass of the liquid calculated above by the volume of the liquid.) Trial 1: 1.278 Trial 2: 1.259 Trial 3: 1.258 Part II: Density of Irregular-Shaped Solid Calculate the volume of the irregular-shaped solid for each trial. (Subtract the volume of the water from the total volume of the water and solid.) Trial 1: 5 Trial 2: 5 Trial 3: 5 Calculate the density of the irregular-shaped solid for each trial. (Divide the mass of the solid by the volume of the solid calculated above.) Trial 1: 8.4186 Trial 2: 8.3804 Trial 3: 7.8434 Compare the density values. Are they precise and accurate? Explain your answers completely. Yes because they are very similar with the only differences mostly being the decimal numbers. Write a conclusion statement that addresses the following questions: Do your data support or fail to support your hypothesis (include examples)? Describe the pattern observed in volume measurements as different masses or volumes of the unknown solid or liquid were selected. Explain why this pattern exists. How do you think the investigation can be explored further? My data supports my hypothesis very strongly. I said in my hypothesis that the solid would have a higher density than the liquid which was the exact outcome shown by the experiment.

Post-Lab Reflection Questions Answer the reflection questions using what you have learned from the lesson and your experimental data. It will be helpful to refer to your chemistry journal notes. Answer questions in complete sentences. How would you determine the proper number of significant figures for measurement of a liquid using a graduated cylinder? You would have to precisely measure/count the numbers on the cylinder Can just one measurement be considered precise? Can just one measurement be considered accurate? Explain your answers completely. No because you need more then one try to make sure you completed the lab correctly. For a boat to float on water, it must have a density lower than the density of water. Compare the densities of your unknown liquid and solid. If a boat was made of the unknown solid, would it float on the unknown liquid? Explain your answer. It would not float because the density would me mush higher than the liquid....