1) If the barometer reading is recorded to be higher than the actual value. What
ID: 909176 • Letter: 1
Question
1) If the barometer reading is recorded to be higher than the actual value. What effect does this error have on the reported value of the molar mass of the compound? Briefly explain (Too High, Too low, Unchanged)
2) If the water bath only reached a temperature of 94.9C but your still used the value of 100C in the calculation what effect would this error have on the reported value for the molar mass of the compound? Briefly explain (Too High, Too low, Unchanged)
3) A 250 mL Erlenmeyer flask has a measured volume of 287mL. The experiment is performed with a this flask but the volume of 250 mL is mistakenly used in the molar mass calculation. What effect does this error have on the reported value? Briefly explain (Too High, Too low, Unchanged)
4) When performing this experiment if your mistakenly added 6 mL of volatile liquid instead of 4 mL at the start. What effect would this have on the calculated value of the molar mass or the compound? Briefly explain (Too High, Too low, Unchanged)
Trial 1 Trial 2 Trial 3 1.Mass of dry flask and foil (g) 96.636 100.551 102.327 2. Temperature of boiling water use 100 (C) 100 100 100 3.Mass of dry flask, foil and vaporized liquid(g) 97.418 101.229 103.061 4. Volume of flask in (mL) 265.5 271.1 271.3 5. Atmospheric Pressure (mmHg) 761.4 761.4 761.4 [6] Moles of vapor from gas law (mol) 0.00869 0.00886 0.00887 [7] Mass of vapor collected (g) 0.782 0.678 0.734 [8] Calculated molecular weight of vapor (g/mol) 89.98849 76.5237 82.75085 [9] Averaged molecular weight (g/mol) 83.08768003 [10] Percent error for each trial 6.93% 9.07% 1.07% [10] Average percent error 5.69%Explanation / Answer
If the barometer reading is recorded to be higher than the actual value means the higher the pressure the more moles are in the flask.
Because
n = PV/RT
So if we read the pressure higher than the actual value, we will calculate a larger number of moles in the flask then there actually are. As the result of this we will lead to a lower molar mass than the actual value.
Molar mass = amount in g/ number of moles
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