pierelably distilled) utel [Erlenmeyer flask 1] and stir gently for 5 minutes. t
ID: 575350 • Letter: P
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pierelably distilled) utel [Erlenmeyer flask 1] and stir gently for 5 minutes. to the solid in the Erlenmeyer flask 5. Weigh a new clean, dry Erlenmeyer flask [Erlenmeyer flask 2]. 39.3 Measure or calculate and record the following (in grams) a) mass of the empty Erlenmeyer flask 1: 42.70 42.40 b) mass of the Erlenmeyer flask 1 plus the 45.01g mixture sample: c) mass of the mixture sample: d) mass of the Erlenmeyer flask 1 and the 2-11g remaining contents after drying of sand: 2nd weighing) sand in the sample: e) mass of Erlenmeyer flask 1 and dry sand 44.15 44 f) Subtract (a) from (e) to obtain the mass of.05 Measure or calculate and record the following (in grams): 39.34 g) mass of an empty Erlenmeyer flask 2: h) mass of Erlenmeyer flask 2 and dry NaC i) mass of Erlenmeyer flask 2 and dry Naci j) mass of Erlenmeyer flask 2 and dry NaCl k) measured mass of dry NaCl: |41.2 3 41.IS 41.29 (1st weighing) (2nd weighing) (3d weighing) if necessary 4l 2. |00.05% .93q signment Questions (all work must be shown for all calculations):Explanation / Answer
4) % difference=(measured mass-mass by substraction)/mass by substraction *100
For NaCl,
measured mass of dry NaCl=1.93g
mass by substraction,(1st weighing)=41.25g-39.34g=1.91g
mass by substraction,(2nd weighing)=41.28g-39.34g=1.94g
average mass by substraction=(1.91+1.94)/2=1.925 g
% difference=(1.93-1.925)/1.925 *100=0.26%
5)mass % of SiO2(sand)=(mass of sand/mass of sample)*100=(2.05/2.97)*100=69.0%
mass % of NaCl=(1.93g/2.97g)*100=65.0%
6) yes ,the percent difference was <10% ,because the method of substraction was in precision with the measured mass,
The mass % of NaCl and sand does not add up to give 100% but (69.02+65=134%).This may be due to the water content of the sample (not properly dried) or error in measurements.
Using two different erlenmeyer flasks with different precision of measurements may have given varied measurement of masses for NaCl and SiO2.Also the apparatus used were not callibrated to find the +/-error in their measurements
These errors could be avoided to reach accurate value for the calculations
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