Common Laboratory Procedures
Laboratory Experiment No. 1: Common Laboratory Procedures
Objective In this experiment, the objectives were to use a balance and measure the volume of the liquids.
Theory
In the experiment, three calculations were used. These are the density, relative error and the standard deviation. Density is refers to the mass (m) per unit volume (V) of a material and is often represented by the symbols d or ρ, where d = m/V. The density of an object changes with pressure and temperature. Second, relative error is a calculated by finding the difference between the true and measured values and dividing this difference by the true answer. And, the standard deviation is the measure of the spread of dispersion of scores (density) from the mean in distribution. Scientists and statisticians use the standard deviation to determine how closely sets of data are to the mean of all the sets. (Analytical Chemistry and Quantitative Analysis, 2011). density = mass of water, gvolume of water, mL (1.1) relative error=|experimental value-accepted value|accepted valuex 100% (1.2) standard deviation=(ρ-)2n-1 (1.3)
A. Using a Pipet to Measure Volume
Materials and Equipment B.
10 mL volumetric pipet
Pipet rubber stopper
(2) 150 mL beaker w/ 50 mL grad. mark
(2) 125 mL Erlenmeyer flask
Thermometer
Balance
Wash bottle
Deionized water
Procedures
Let stand the 400 mL beaker filled with deionized water for 15 minutes to adapt with the room temperature and measure the temperature of the water. Measure and record the mass of an empty Erlenmeyer flask. After that, use a pipet to deliver 10 mL of the water from the beaker into the Erlenmeyer flask. Measure the mass of water and flask. For the next two trials, without emptying the flask, deliver 10 mL of water to it. Calculate the density of the water for the three trials and calculate the average density and standard deviation.
Data
Mass of empty Erlenmeyer flask = 98.320 g
Room temperature and of
Objective In this experiment, the objectives were to use a balance and measure the volume of the liquids.
Theory
In the experiment, three calculations were used. These are the density, relative error and the standard deviation. Density is refers to the mass (m) per unit volume (V) of a material and is often represented by the symbols d or ρ, where d = m/V. The density of an object changes with pressure and temperature. Second, relative error is a calculated by finding the difference between the true and measured values and dividing this difference by the true answer. And, the standard deviation is the measure of the spread of dispersion of scores (density) from the mean in distribution. Scientists and statisticians use the standard deviation to determine how closely sets of data are to the mean of all the sets. (Analytical Chemistry and Quantitative Analysis, 2011). density = mass of water, gvolume of water, mL (1.1) relative error=|experimental value-accepted value|accepted valuex 100% (1.2) standard deviation=(ρ-)2n-1 (1.3)
A. Using a Pipet to Measure Volume
Materials and Equipment B.
10 mL volumetric pipet
Pipet rubber stopper
(2) 150 mL beaker w/ 50 mL grad. mark
(2) 125 mL Erlenmeyer flask
Thermometer
Balance
Wash bottle
Deionized water
Procedures
Let stand the 400 mL beaker filled with deionized water for 15 minutes to adapt with the room temperature and measure the temperature of the water. Measure and record the mass of an empty Erlenmeyer flask. After that, use a pipet to deliver 10 mL of the water from the beaker into the Erlenmeyer flask. Measure the mass of water and flask. For the next two trials, without emptying the flask, deliver 10 mL of water to it. Calculate the density of the water for the three trials and calculate the average density and standard deviation.
Data
Mass of empty Erlenmeyer flask = 98.320 g
Room temperature and of