Density Lab Report

PURPOSE:
a. To measure the masses and volumes of solids and liquids b. To calculate the densities of solids and liquids
c. To calculate the specific gravities of solids and liquids d. To calculate the volume of a rectangular object and to express the volume in volume metric units e. To record data and calculate the values in the correct number of significant figures MATERIALS:

10 mL graduatebalancetest tube rackunknown liquid
50 mL graduatetest tube100 mL beakerassorted solid objects Dropper pipettemeter stick

PROCEDURE:

Part A. Density of Water
1. Measure the mass of a 100 mL beaker to the nearest .01 g. The beaker should be dry. 2. Measure, as accurately as possible, 50.0 mL of water. Use the graduated cylinder (the bottom of the meniscus must be on the 50 mL mark. You may want to use the dropping pipette to add the last few drops of water to get exactly 50.0 mL). Add this measured volume of water to the 100 mL beaker. 3. Measure the mass of the beaker and the water. Record all measured values in the data chart for Part A of the observation section of your lab report.

All of the data charts should have two columns, one for the item measured and one for the value. The data chart for Part A should contain the following information: (*refers to calculated or theoretical values) A. Mass of the empty beaker D. *Mass of the water G. *Percent Error B. Volume of the water E. *Density of water (experimental) C. Mass of the beaker and water F. *Density of water (theoretical) Part B. Density of an Unknown Liquid

1. Measure the mass of a 10 mL graduated cylinder.
2. Fill the graduated cylinder close to the 9 mL mark with the unknown liquid. Read the volume to the nearest 0.1 mL or 0.2 mL according to the precision of the graduate. 3. Measure the mass of the cylinder and its contents carefully. Record all measured values in the data chart for Part B in the observations section of your lab report. 4. Return the unknown liquid to a container designated by your teacher. Do not return it to the reagent bottle!

The data chart for Part B should contain the following information: (* refers to calculated or theoretical values) A. Mass of the empty graduated cylinder E. *Density of unknown liquid (experimental) B. Volume of the unknown liquid F. *Specific gravity of unknown (experimental) C. Mass of the liquid and graduated cylinder G. *Specific gravity of unknown (theoretical) D. *Mass of unknown liquid H. *Percent error for specific gravity Part C. Density of a Solid

1. Obtain a solid object from your instructor and measure its mass to the nearest .01 g. 2. Fill a 50 mL graduated cylinder close to the 25 mL mark. Record the volume of water to the nearest .1 mL. 3. Tilt the graduated cylinder carefully and slip the solid object down the inside of the cylinder into the water. Be cautious. Do not allow any of the water to splash out of the cylinder and do not drop the object because you may break the cylinder! Record the new volume of the contents of the graduated cylinder to the nearest .1 mL. Record all measured values in the data chart for Part C in the observations section of your lab report. 4. Return the solid object to the area designated by your instructor.

The data chart for Part C should contain the following information: (* refers to calculated or theoretical values) A. Mass of the solid object E. *Density of solid (experimental) B. Original volume of water F. *Specific gravity of solid (experimental) C. Volume of water and solid G. *Specific gravity of solid (theoretical) D. *Volume of solid H. *Percent error for specific gravity Part D. Calibration

1. Use a dropper pipette to determine the number of drops in 5.0 mL of water. Hold the dropper pipette vertically while counting the drops into a 10 mL graduated cylinder. 2. Fill a test tube with water (to the brim). Pour the water into a 50 mL graduated cylinder and record the volume to the nearest 01 mL.

The observations section of your lab report should include a Part D with a place to record the results to #1 and #2.

Part E. Calculated volume of a Regular Shaped Object
3. Examine a meter stick and note its major and minor divisions. 4. Record the dimensions of one of the lab’s island sinks to the nearest 0.10 cm. 5. Calculate the volume of the sink in cm3, dm3, m3, mL, and L. The observations section of your lab report should include a Part E with a place to record your observations for #1 and the dimensions for the sink in #2 (length, width, depth). DATA

Raw Data:
Part A – Water:
Type of Measurement| Value|
Mass of Graduated Cylinder| 36.79 g +/- 0.02 g|
Volume of Water| 10 mL +/- 0.01 mL|
Mass of Graduated Cylinder and Water| 46.77 g +/- 0.03 g|

Part B – Alcohol
Type of Measurement| Value|
Mass of Graduated Cylinder| 36.86 g +/- 0.05 g|
Volume of Alcohol| 10 mL +/- 0.02 mL|
Mass of Graduated Cylinder and Alcohol| 45.54 g +/- 0.04 g|

Part C – Marble Ball
Type of Measurement| Value|
Mass of Object | 5.00 g +/- 0.02 g|
Volume of Water | 10 mL +/- 0.01 mL|
Volume of Water w/ Marble Ball| 12 mL +/- 0.004 mL|

Calculated Data: Density = M/V or g/mL
Part A: 46.77g – 36.79 = 9.98 g Water
9.98g/10mL = .998 = 1.000 g/mL
Part B: 45.54g – 36.86g = 8.62 g
8.62g / 10.0 mL = 0.868 g/mL
Part C: 12mL – 10mL = 2 mL
5.00g/2mL = 2.5 g/mL

CONCLUSSION:
In conclusion, we were able to conduct this lab successfully. In this lab, we calculated the density of water, alcohol, and a marble. We used a variety of materials to conduct this lab. First off, we used an electronic scale to find the exact mass of the objects. We used the graduated cylinder for two things. First off, we used it when we determining the mass of the water. Basically, we would find the before and after mass of the graduated cylinder and subtract the two numbers. We also used it to calculate the volume of the marble by using water displacement. Basically, you drop the marble in the water and the volume is calculated using the before and after volumes.

During this lab, we encountered a few errors. First off, the electronic was very accurate. For instance, for one trial, the graduated cylinder weighed 36.79 g, but it said that is weighed 36.86 g in the next trial. This was most likely caused by a difference in atmospheric pressure during the weightings, most likely caused by the Air Conditioner. Also, we were not able to completely clean out the graduated cylinders. This meant that was a small amount of water in the bottom of the graduated cylinder, most likely adding weight to the graduated cylinder. This means that our readings were most likely inaccurate, causing many flaws when we calculated the density of the substances.

Some of the ways that we could’ve improved the results of the lab is if we conducted the experiment without any air conditioner so that the air pressure would affect the sensitive electronic scale a lot less. Also, I wish that we were able to use different graduated cylinders for each trial. This would increase the validity of our results because the graduated cylinders would be completely dry, which means that there would be no liquid that would make the graduated cylinders weigh more, thus making our results and calculations much more valid. All in all, both of these things would’ve made our lab a lot better and more accurate.