# Module 01 lab 01 – uncertainty, measurements, and significant figures

Purpose of Experiment: To become familiar with the virtual lab software, solutions, glassware and tools available. To gain a better understanding of uncertainty, how to take measurements and how to report significant figures properly.

Chemicals and Materials:

Distilled H2O
5 mL Pipette
250 mL Beaker
Scale
Solid Sodium Chloride
Weigh Boat

Deliverables:

• Record of all observations.
• Calculations for conversions, scientific notation, and significant figures.

Instructions for Virtual Lab: Record all observations.

Go to lab page: http://www.chemcollective.org/vlab

1. From the stockroom in the Virtual Lab, obtain glassware, solutions/solids, and a scale.
2. Fill the 250 mL Beaker using the realistic tab with approximately 200 mL of H2O.
3. Using the 5 mL Pipette and the realistic tab, draw up approximately 5 mL of water.
4. Using the realistic tab, press the hold to pour button until you have dispensed at least 2 mL of water into the graduated cylinder.
5. Reading the meniscus, record and report with the correct significant figures the volume of liquid dispensed.
6. Obtain the scale and a 250 mL Flask.
7. Place the flask on the scale and record the weight of the flask.
8. Using the “tare” button, tare the weight of the flask, pour the water from the graduated cylinder into the flask and record the weight of the water to the three significant figures.
9. Remove all items except the scale from the workbench.
10. Obtain a weigh boat from the stockroom glassware under other.
11. Place the weigh boat on the scale and record its weight.
12. Tare the weight of the weigh boat.
13. Obtain the NaCl (sodium chloride) from the stockroom solutions under solids.
14. Using the realistic tab, transfer two scoopulas full onto the weigh boat and record the weight of the sodium chloride with three significant figures.

Instructions for Calculations: Complete the following calculations for conversions, scientific notation, and significant figures.

Convert the following:

1. 23 yd. =___ m
2. 4 km =____ mi
3. 78 kg =____ lbs.
4. 4 g =___ oz.
5. 5.3 gal =____L

Convert following numbers into or out of scientific notation:

1. 20,452,384
2. 3 x 103
3. 0.03498
4. 0.00004928
5. 2.983 x 10 -4

Perform calculations and report answers with correct significant figures. Use scientific notation when needed.

1. 2.04 + 0.334 =
2. 20.33 – 0.2 =
3. 409 x 22.44 =
4. 3.0/29 =
5. 29,004 x 2.0 =
6. (2.6 – 0.67) x 4.0 =
7. 4.1(3.8 – 0.04)/3.46 =