LAB 1 – Biology Lab Skills

AP Biology—Lab 01
Table 5: Mass of water volumes measured using a 25 mL Erlenmeyer flask.
Total volume of
water (mL)
Total calculated
mass of water
(g)
Total measured
mass of water
(g)
Calculated mass
of water added
in this step (g)
Measured mass
of water added
in this step (g)
Error
Percent Error
20.0 20.0
40.0 40.0
60.0 60.0
80.0 80.0
100.0 100.0
Mean Values:
Procedure 6:
The accuracy of 50 mL volumetric flask
1. Using a 400 gram top-loading balance, tare a dry 250 mL beaker.
2. Using a 50 mL volumetric flask, as carefully as possible, measure 50 mL of de-ionized
(DI) water.
3. Pour this measured amount of water into the 250 mL beaker.
4. Record the mass of the water to the nearest 0.01 g in Table 6.
5. Pour the contents in the 250 mL beaker down the sink, return to the top-loading
balance, and tare.
6. Again, using the 50 mL volumetric flask, measure 50 mL of water and add it to the 250
mL beaker.
7. Record the mass in Table 6.
8. Repeat steps 5 – 7 for a total of 5 measurements.
9. Calculate the error columns in Table 6.
Table 6: Mass of water volumes measured using a 50 mL volumetric flask.
Volume of
water (mL)
Calculated mass
of water added
in this step (g)
Measured mass
of water added
in this step (g)
Error
Percent Error
50.0
50.0
50.0
50.0
50.0
Mean
Values:
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