from aide_design .play import * Datasheet for Week 2 Lab: Laboratory Measurements
Balance Calibration
value
Balance ID
Mass of calibration mass
2nd mass used to verify calibration
Measured mass of 2nd mass
Temperature Measurement
value
Distilled water temperature
Pipette Technique (use DI-100 or Ohaus 160 balance)
value
Density of water at that temperature
Actual mass of 990 µL of pure water
Mass of 990 µL of water (rep 1)
Mass of 990 µL of water (rep 2)
Mass of 990 µL of water (rep 3)
Mass of 990 µL of water (rep 4)
Mass of 990 µL of water (rep 5)
Average of the 5 measurements
Standard deviation of the 5 measurements
Precision
value
Percent coefficient of variation of the 5 measurements
Accuracy
value
average percent error for pipetting
Percent error for pipetting is calculated as follows:
$100*\frac{\left | mass_{density} - mass_{balance} \right |}{mass_{density}}$
Measure Density (use DI-800 or Ohaus 400D or Prec. Std)
value
Molecular weight of NaCl
Mass of NaCl in 100 mL of a 1-M solution
Measured mass of NaCl used
Measured mass of empty 100 mL flask
Measured mass of flask + 1M solution
Mass of 100 mL of 1 M NaCl solution
Density of 1 M NaCl solution
Literature value for density of 1 M NaCl solution
percent error for density measurment
Prepare methylene blue standards of several concentrations
value
Volume of 1 g/L MB diluted to 100 mL to obtain:
1 mg/L MB
2 mg/L MB
3 mg/L MB
4 mg/L MB
5 mg/L MB
Absorbance of unknown at 660 nm
Calculated concentration of unknown
Measure absorbance at 660 nm using a spectrophotometer
value
Absorbance of distilled water
Absorbance of 1 mg/L methylene blue
Absorbance of 2 mg/L methylene blue
Absorbance of 3 mg/L methylene blue
Absorbance of 4 mg/L methylene blue
Absorbance of 5 mg/L methylene blue
Slope at 660 nm (m)
Intercept at 660 nm (b)
Correlation coefficient at 660 nm (r)
Calculated concentration of unknown