Online Chemistry Laboratory 2
Techniques and Measurements
This is the first lab in the lab manual, pages 14-48. Read through the introduction in the lab manual up to page 28. You may skip the section “Amount of Substance and Concentration” that starts at the bottom of page 28 (we do not discuss concentration until Chapter 9).
Complete exercises 1 and 2, pages 31-36. Use the report pages below to record your data. Answer questions A-G found on pages 46 and 47.
Lab 2 Report
Data Table 1: Length Measurements |
Object | Length (cm) | Length (mm) | Length (m) |
CD or DVD | 12.1 cm | 121 mm | .121 m |
Key | 5.1 cm | 51 mm | .051 m |
Spoon | 16.1 cm | 161 mm | .161 m |
Fork | 18.5 cm | 185 mm | .185 m |
NOTE: The instructions indicate to measure the objects to “one degree of uncertainty.” The degree of uncertainty is a property of the instrument used. All three recorded values will have the same precision. On page 29 is the explanation of uncertainty. The concept is illustrated in Figure 13 on page 30. I expect your report will include length to 0.1 cm, a whole mm, and to 0.001 m. As an example, a sheet of paper is 21.6 cm, 216 mm, or 0.216 m wide. In each case, the measurement is precise to 1 mm (which is 0.1 cm and 0.001 m). The first degree of uncertainty is at the mm length.
Data Table 2: Temperature Measurements |
Water | Temperature (oC) | Temperature (K) |
Hot from Tap | 39 C | 312 K |
Boiling | 99 C | 372 K |
Boiling for 5 minutes | 101 C | 374 K |
Cold from Tap | 11 C | 284 K |
Ice water – 1 minute | 6 C | 279 K |
Ice water – 5 minutes | 3 C | 276 K |
NOTE: We will not use the Fahrenheit scale.
Data Table 3: Mass Measurements |
Object | Estimated Mass (g) | Actual Mass (g) | Actual Mass (kg) |
Pen or pencil | 4.5g | 5.1 g | .0051 kg |
3 Pennies | 10.5g | 8.7 g | .0087 kg |
1 Quarter | 5.5g | 5.7 g | .0057 kg |