Procedure
A. Measuring the Volume of Liquids Using Beakers
Fill the 50 mL beaker with water as full as it can possibly be without spilling. Transfer the liquid to the 100 mL beaker and record the volume on your report sheet. Be careful to record the volume to the proper number of significant figures; Remember: the measured volume should include all of the certain digits, which are determined using the graduation marks on the container, plus one more uncertain digit, which is determined by estimating where the level of the liquid falls between the graduation marks. Then transfer the water to the 500 mL beaker and record the volume on the report sheet. Transfer the water one last time, this time to the 1000 mL beaker and record the volume on the report sheet. . Take a picture to upload with your report.
B. Measuring the volumes of Liquids using Graduated Cylinders
Fill the 50 mL beaker with water to approximately 20 mL. Transfer the liquid to the 25 mL graduated cylinder and record the volume on your report sheet. Be careful to record the volume to the proper number of significant figures; Remember: the measured volume should include all of the certain digits, which are determined using the graduation marks on the container, plus one more uncertain digit, which is determined by estimating where the level of the liquid falls between the graduation marks. Then transfer the water to the 50 mL graduated cylinder and record the volume on the report sheet. Transfer the water one last time, this time to the 100 mL graduated cylinder and record the volume on the report sheet. Take a picture to upload with your report.
C. Measuring the Volume of an Object with Regular Shape
Choose an object with a regular shape such as a book, a box, a ball, etc., and describe it on your report sheet. Measure the dimensions of the object in centimeters, then use the appropriate formula to calculate the volume of the object in cubic centimeters. Convert this volume into milliliters (1 mL = 1 cm3), liters (1 L = 1 dm3), cubic meters, and cubic inches (1 in = exactly 2.54 cm). Show all of your calculations.
D. Measuring the Volume of an Object with Irregular Shape
Choose an object with irregular shape such as a rock, a small piece of metal, etc. that can fit easily into the 100 mL graduated cylinder, and describe it on your report sheet. Partially fill the 100 mL graduated cylinder with water such that the object will be completely submerged when placed into it, but the level of the water will remain below the maximum 100 mL mark. Record the initial volume. Place the irregular shaped object into the graduated cylinder and record the new volume. Take a picture of the object in the graduated cylinder and upload this with your Report Sheet. Calculate the volume of the object by taking the difference between the two recorded volumes, and record the final volume on your report sheet.
Use the same irregular shaped object to perform the volume measurement using the 100 mL beaker. Partially fill the 100 mL beaker with water such that the object will be completely submerged when placed into it, but the level of the water will remain below the maximum 100 mL mark. Record the volume. Place the irregular shaped object into the graduated cylinder and record the new volume. Calculate the volume of the object by taking the difference between the two recorded volumes, and record the volume on your report sheet.
Pre-Laboratory Questions
What is a meniscus? Sketch a 10 mL graduated cylinder filled to a volume of 5.24 Ml.
How do we typically read the liquid level when dealing with a liquid that forms a meniscus? Describe how to read a volume using a graduated cylinder with graduation marks every 1 mL.
Why is a rubber safety bulb always used when working with a pipet?
Why are the calibration marks on laboratory beakers taken only to be an approximate guide to volume?
Precision volumetric glassware (pipets and burets) may be marked with the legend “TC” or “TD” along with a temperature. To what do each of these notations refer?
Results and Observations
A. Measuring the Volume of Liquids Using Beakers
Volume of water measured in the 100 mL beaker:
Volume of water measured in the 500 mL beaker: _
Volume of water measured in the 1000 mL beaker:
B. Measuring the volumes of Liquids using Graduated Cylinders
Volume of water measured in the 25 mL graduated cylinder: _
Volume of water measured in the 50 mL graduated cylinder: _
Volume of water measured in the 100 mL graduated cylinder:
C. Measuring the Volume of an Object with Regular Shape
Description of the object:
Dimensions of the object in centimeters (cm): Volume in cubic centimeters (cm3):
Volume in milliliters (mL): Volume in liters (L):
Volume in cubic meters (m3): Volume in cubic inches (in3):
D. Measuring the Volume of an Object with Irregular Shape
Description of the object:
Volume Using a 100 mL Graduated Cylinder
Initial volume:
Final volume:
Volume of the object:
Volume Using a 100 mL Beaker
Initial volume: _
Final volume:
Volume of the object:
* Upload one picture for each part of the lab (A, B, and C) with your report sheet
Post-Laboratory Questions
How does the ~20 mL volume measured by the graduated cylinders compare to the volumes as determined in using a beaker? Do beakers tend to be more or less precise than graduated cylinders?
Which measuring device (beaker graduations or graduated cylinder) and size gives the greatest precision?
On the basis of your experience in this experiment, briefly discuss the relative precision permitted by a graduated cylinder and a beaker. Give several circumstances under which you would use each instrument, in reference to the other two.
Pipets used for the transfer of samples of aqueous solutions are always rinsed with a small portion of the solution to be used before the sample is taken. Calculate the percentage error arising in an experiment when 1 mL, 5 mL, and 10 mL pipets are used for transfer and each pipet contains 5 drops of water adhering to the inside of the barrel. Note: A single drop of water has an approximate volume of 0.05 mL.
It is important to make certain that there is no air bubble in the tip of the buret below the stopcock before the initial reading of the liquid level in the buret is taken. If a 0.5-mL air bubble is present in the tip of a buret, what percent error in 10 mL, 20 mL, and 40 mL samples will result if the air bubble is dislodged during the dispensing of the samples?
