Lab 8
Mole Baggie Lab
Shiva Senthil
7/21/17
Introduction
The purpose of this lab was to identify compounds given either the number of moles or the number of particles in a bag of the substance. The compounds were weighed and that and the given measurements were used to calculate the molar mass and then identify the compound in the bag.
Data
The first step of the process was to find a formula to be able to use the mass and the given measurement to determine the molar mass (g/mol). The given measurement for each bag was different, so the formulas were slightly different. The next step was to measure the mass and subtract the given mass of the bag. The last step was to actually calculate the molar mass and identify the substance from one of five given compounds (sodium chloride [molar mass 58.44 g/mol], potassium sulfate [MM 174.3 g/mol], zinc oxide [MM 81.40 g/mol], sodium sulfate [MM 142.0 g/mol], and calcium carbonate [MM 100.1 g/mol]).
Bag A2:
Since the number of moles is given and the mass is measured, to find the molar mass, all that needs to be done is divide the number of grams by the number of moles:
Plugging in the grams and the moles results in the molar mass:
The molar mass of the substance in bag A2 is about 173 g/mol. The closest to this number is the 174.3 g/mol of potassium sulfate. Thus, the substance in bag A2 is potassium sulfate.
Bag B6:
Since the number of representative particles is given and the mass measured, the number of particles must be converted to moles before dividing the grams by the moles:
Substituting this equation in for the mole in the basic molar mass equation results in:
After simplification:
Then, the mass and number of representative particles is substituted in and calculated:
The molar mass is about 84.8 g/mol, which is closest to zinc oxide (81.41 g/mol). Therefore, the substance in bag B6 is zinc oxide.
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