Introduction: In this lab, we will be performing a number of experiments to practice basic laboratory techniques, that are necessary for the success of future lab experiments. Chemistry is an experimental science that depends on careful observation and the use of good laboratory techniques. We will perform four mini-labs: The Meterstick, The Graduated Cylinder, The Thermometer and Its Calibration, and Using the Balance to Calibrate You 10 mL Pipette. In each mini-lab, we will carefully use correct units and measurements to solve solutions as well as interpret our data and observations. These 4 mini-labs focus on measuring mass, volume, length, and temperature. We learned of the metric system and SI units prior to this lab. In The Meterstick
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Meterstick Data
Units of Measurement
Measurements
Inches (in)
11 in x 8.875 in
Centimeters (in)
27.9 cm x 22.5 cm A meter stick is a measuring object that measures in inches on one end and centimeters on another end. Theoretically, if we measured our book in inches and centimeters, converting one unit to another should end up in the same measurements. By performing dimensional analysis using conversion factors, we can test this theory:
Known: 1 inch = 2.54 cm, 2.54 cm = 1 inch
11 in x (2.54 cm / 1 in) = 27.9 cm, 8.875 in x (2.54 cm / 1 in) = 22.5 cm
27.9 cm x (1 in / 2.54 cm) = 11 in, 22.5 cm x (1 in / 2.54 cm) = 8.875 in
Graduated Cylinder Data
Volume (to the nearest 0.1 mL)
100 mL beaker
54.7 mL
Test …show more content…
By isolating volume, we will end up with the equation, Volume = Mass / Density. The density of the water at different temperatures is outlined on a table provided by our lab instructor. At 18°C, water possesses the density of 0.998595 grams per milliliter, or g/mL. By dividing the mass of water obtained in the three trials with this density, we will end up with the volume of the pipet.
Trial 1: 10.5 g / 0.998595 g/mL = 10.51 mL
Trial 2: 10.9 g / 0.998595 g/mL = 10.91 mL
Trial 3: 9.9 g / 0.998595 g/mL = 9.912 mL
The precision of a measurement is a statement about the internal agreement among repeated results; it is a measure of the reproducibility of a given set of results. The arithmetic mean, or average, is known as the best value. The simplest measure of precision is the average deviation from the mean, which is calculated by determining the mean of the measurements and calculating the deviation of each measurement from the mean. Thus:
Deviation from the mean: |value - mean|
Average Deviation: Deviations / # of Deviations
Mean: (10.51 mL + 10.91 mL + 9.912 mL) / 3 =
Meterstick Data
Units of Measurement
Measurements
Inches (in)
11 in x 8.875 in
Centimeters (in)
27.9 cm x 22.5 cm A meter stick is a measuring object that measures in inches on one end and centimeters on another end. Theoretically, if we measured our book in inches and centimeters, converting one unit to another should end up in the same measurements. By performing dimensional analysis using conversion factors, we can test this theory:
Known: 1 inch = 2.54 cm, 2.54 cm = 1 inch
11 in x (2.54 cm / 1 in) = 27.9 cm, 8.875 in x (2.54 cm / 1 in) = 22.5 cm
27.9 cm x (1 in / 2.54 cm) = 11 in, 22.5 cm x (1 in / 2.54 cm) = 8.875 in
Graduated Cylinder Data
Volume (to the nearest 0.1 mL)
100 mL beaker
54.7 mL
Test …show more content…
By isolating volume, we will end up with the equation, Volume = Mass / Density. The density of the water at different temperatures is outlined on a table provided by our lab instructor. At 18°C, water possesses the density of 0.998595 grams per milliliter, or g/mL. By dividing the mass of water obtained in the three trials with this density, we will end up with the volume of the pipet.
Trial 1: 10.5 g / 0.998595 g/mL = 10.51 mL
Trial 2: 10.9 g / 0.998595 g/mL = 10.91 mL
Trial 3: 9.9 g / 0.998595 g/mL = 9.912 mL
The precision of a measurement is a statement about the internal agreement among repeated results; it is a measure of the reproducibility of a given set of results. The arithmetic mean, or average, is known as the best value. The simplest measure of precision is the average deviation from the mean, which is calculated by determining the mean of the measurements and calculating the deviation of each measurement from the mean. Thus:
Deviation from the mean: |value - mean|
Average Deviation: Deviations / # of Deviations
Mean: (10.51 mL + 10.91 mL + 9.912 mL) / 3 =