Post-Lab 1: Chem 103

What piece of glassware fits the rubber stopper #5?

side arm flask

What piece of glassware is used with the pipet pump?

Mohr pipet

What piece of equipment should be used to stir a solution?

glass stirring rod

What piece of equipment should be used to measure solids at the balance?

weigh boat and spatula/spoonula

What piece of equipment should be used to hold or carry the crucible?

crucible tongs

What piece of equipment should be taken with you to the dispensing station to obtain solutions?

beaker

What piece of equipment should be used to prepare a solution of known concentration?

volumetric flask

What piece of equipment should be used to guide liquid into a small opening, such as a buret?

gravity funnel

What items should be used to clean glassware?

brushes (large or small), soap and water

What items should be used to clean the OAS bench-tops at the end of the laB?

sponges, soap and water

Which piece of equipment can withstand very high temperatures?

crucible

Select all of the statements that are true when using an electronic balance.

- The "tare" button on the balance "zeros" the mass located on the balance pan.

- There are two methods of determining the mass of a substance in a weigh boat when using the electronic balance.

Select all of the statements that are true when using an electronic balance.

- Leaving a spilled chemical on the balance can permanently damage the balance.

- Each student should clean the balance area after weighing out a chemical.

- The paintbrush located at each balance can be used to "brush away" any solid chemical that spills on the balance pan.

How many decimal places are on the electronic balance?

3

You were tasked with measuring 1.250 g of lentil beans. Given simulated masses for the extra lentils from each trial performed in the lab given in the table below, calculate the percent (by mass) of extra lentils that were used in each of these trials.

Trial 1(mass of extra beans calculated): 0.154 g

Trial 2(mass of extra beans calculated): 0.113 g

Trial 3(mass of extra beans calculated): 0.259 g

Trial 4 (mass of extra beans calculated): 0.010 g

Trial 1 (percent extra beans): 12.3%

Trial 2 (percent extra beans): 9.04%

Trial 3 (percent extra beans): 20.7%

Trial 4 (percent extra beans): 0.80%

Calculate the average percent extra beans for your 4 trials.

10.7%