Objective:
The purpose of this experiment is to see the difference of precision of different balances. When doing experiments we determine the mass my measuring the sample with a balance. There are many kinds of balances that measure to different precisions. This experiment shows the different results that two balances can give.
Summary of Procedures
Determine the mass with the triple beam scale to the most precise measurement possible for the scale. First we measure the mass of the beaker. We measure the beaker with the sample inside it and subtract the beakers weight. This will give us an accurate measurement of the sample. Repeat exercise with electronic scale. Figured out the difference in precision of the scales.
Pre-laboratory Questions
What are the differences in meaning between mass and weight? IN the laboratory, do we determine the mass or the weight of objects?
Mass is the measurement of matter of an object. Weight is the response of mass to gravity. The mass does not change with gravity but the weight does. In the laboratory we are measuring the weight of the sample since can’t measure its mass without gravity.
Explain the following. Weigh approximately 5 grams of NaCl to the nearest milligram.
The weight of 5 grams of NaCl is equal to 5,000 milligrams. We convert grams to milligrams by multiply grams by a 1,000.
Data tables
Triple beam balance
Mass of empty beaker : 66.60 g
ID number of object Mass of beaker plus object Mass of object itself
Sample 18-A 69.20 g 2.60 g
Sample 18-B 99.52 g 32.92 g
Sample 18-C 77.72 g 11.12 g
Electronic balance
Mass of empty beaker : 66.60 g
ID number of object Mass of beaker plus object Mass of object itself
Sample 18-A 69.293 g 02.635 g
Sample 18-B 99.507 g 32.849 g
Sample 18-C 77.694 g 11.036 g
Difference in masses determined on the two balances
Id number of object Mass of object itself
Sample 18-A 0.04 g
Sample 18-B 0.07 g
Sample 18-C