Pre-Lab Quiz-Glassware, Techniques, and Measurement

Suppose you place 3.31 mL of a substance into a graduated cylinder. The graduated cylinder has a mass of 12.55 g when empty and a mass of 15.57 g after adding the substance. What is the density of the substance (in g/mL)?

0.9 g/mL

What is the mass (in g) of a diamond that occupies 3.13 mL if the density of diamond is 3.51 g/mL?

11 g

Rank the following glassware used in lab from least accurate (1) to most accurate (3). Volumetric pipette ___ Beaker ___ Graduated cylinder ___

3 1 2

What is the correct reading of the volume in the pictured buret?

39.95 mL

Suppose you are measuring the mass of a solid sample on a balance using a weigh boat. You record the data in a table. Mass of weigh boat: 1.775 g Mass of weigh boat and sample: 6.248 g What is the mass of the solid sample (in g)?

4.473 g

What is the correct reading for the graduated cylinder in the close-up?

40.5 mL

What is the correct reading of the temperature in the pictured thermometer?

40.6C

What are the best practices while sharing a lab balance with other students?

Alert your TA or instructor about any issues with the balance. Brush off any chemical dust around the balance after each use.

When using a properly stabilized balance, how should you ensure that you get the most accurate mass reading possible?

Close the side shields on the balance during reading. Measure the mass of the sample at room temperature.

What practice will not help you make an accurate volume reading on a buret at the beginning of a titration?

Make sure that the meniscus starts exactly at 0.00 mL.

After clamping a buret to a ring stand, you notice that the set-up is tippy and unstable. What should you do to stabilize the set-up?

Move the buret clamp to a ring stand with a larger base.

Choose the best graduated cylinder to make each measurement in a single use. 36 mL of water __________ 5.75 mL of a sucrose solution _________ 18.5 mL of a NaCl solution ____________

a 50mL graduated cylinder with markings every 10 mL a 10 mL graduated cylinder with markings every 0.1 mL a 25 mL graduated cylinder with markings every 1 mL

Identify which balance was used to make each mass reading. 1.230 g __________ 6.539 g __________ 5.43 g _________ 0.90 g ________ 4.0000 g _________

a balance with +-0.001 g tolerance a balance with +- 0.001 g tolerance a balance with +-0.01 g tolerance a balance with +-0.01 g tolerance a balance with +-0.0001 g tolerance

When using the Tare function on a balance, start by ________. Then, _____________ to cancel out that mass. Finally, _____________ and record the mass of your sample.

placing the glassware on the balance press the Tare/Zero button add your sample to the glassware

To measure out a volume of liquid, start by choosing the appropriate graduated cylinder and moving the bumper to the _____ of the graduated cylinder to protect it from breakage. Then, pour the liquid into the graduated cylinder until the_______ of the meniscus aligns with the desired volume marking when you look at the graduated cylinder from ______

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