Chem 110 Chemistry Glassware and Measurements

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 the Tare function on a balance, start by _______ Then, __________ to cancel out that mass. Finally, _________ and record the mass of your sample.

1. Placing the glassware on the balance 2. press the Tare/Zero button 3. add your sample to the glassware

Determine whether each of the properties described applies to volumetric or graduated glassware. 1. capable of measuring a range of volumes of liquid 2. designed to measure one specific volume of liquid 3. used for applications in which great accuracy is needed

1. capable of measuring a range of volumes of liquid = Graduated 2. designed to measure one specific volume of liquid = volumetric 3. used for applications in which great accuracy is needed = volumetric

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____________.

1. top 2. bottom 3. eye level

Suppose you are titrating an acid of unknown concentration with a standardized base. At the beginning of the titration, you read the base titrant volume as 2.77 mL. After running the titration and reaching the endpoint, you read the base titrant volume as 18.37 mL. What volume, in mL, of base was required for the titration?

15.6 mL

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

25.60 mL

Suppose you are titrating an acid of unknown concentration with a standardized base. At the beginning of the titration, you read the base titrant volume as 1.34 mL. After running the titration and reaching the endpoint, you read the base titrant volume as 28.45 mL. What volume, in mL, of base was required for the titration?

27.11 mL

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 =

36 mL of water = A 50 mL graduated cylinder with markings every 10 mL 5.75 mL of a sucrose solution = A 10 mL graduated cylinder with markings every 0.1 mL 18.5 mL of a NaCl Solution = A 25 mL graduated cylinder with markings every 1 mL

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

40.5 mL

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.