Data from M. J. Samide, J. Chem. Ed. 2004, 81, 1641. (a) Do the volumes delivered by student 1 from the buret and pipet differ at the 95% confidence level? (b) Do the volumes delivered by student 1 from the buret and flask differ at the 95% confidence level? (c) Do the volumes delivered from the pipet by students 1 and 2 differ at the 95% confidence level?

Estimate the absolute deviation(or uncertainty) for the results of the following calculations. Round each result so that it contains only significant digits. The numbers in parentheses are absolute standard deviations. Finally, write the answer and its uncertainty.a.) Y= 6.75 (± 0.03) + 0.843(±0.001) - 5.021 (±0.001) = 2.572b.) Y= 19.97(± 0.04) + 0.0030(±0.0001) + 4.29(±0.08) = 24.263c.) Y= 143(± 6) - 64(±3) = 5.9578 x10-21249 (±1) +77 (±8)

3. How would you solve this ppm Ttest problem?

Is the precision of your two trials within 5 %?. Support your answer with calculations

3-3 Types of Error; 3-4 Propagation of Uncertainty from Random Error (30 min) If A = 3.475 (+0.002), B = 87.336 (±0.001), C = 10.004 5 (±0.000 5), D = 11.8 (+0.2), and E = 5.10 (±0.03), report the answers of the following calculations with both the absolute uncertainty and the percent relative uncertainty. a) (A - B) XE c) b) (C+D)/(AXE) d) [(A+B+C) x (B-C-E)] / [DXE] (10-D)/(E/1000) Answer w/ absolute uncertainty: -428 (13) or -427.7 (±2.5) Answer w/% relative uncertainty: -428 (±0.6%) or -427.7 (±0.5⁹%) b) Answer w/ absolute uncertainty: 1.23 (±0.01) or 1.230 (+0.013) Answer w/ % relative uncertainty: 1.23 (±1%) or 1.230 (+1.1%) Answer w/ absolute uncertainty: 3 (±1) x 10-10 or 3.1 (±1.4) × 10-10 Answer w/ % relative uncertainty: 3 (±50%) x 10-10 or 3.1 (±46%) × 10-10 Answer w/ absolute uncertainty: 121 (±2) or 121.0 (+1.4) Answer w/ % relative uncertainty: 121 (±2%) or 121.0 (±1.8%)

4

Consider the following SAS data and formula. Volume of sample at $1%: 50.2 ml 51% = 55% 52% = 70% Volume of SAS = [(volume of sample at S1%) (S2% - S1%)] / 100 [(1-(S2% / 100)] Calculate the volume of SAS needed for this experiment given this information.

You are in the lab preparing copper solutions for the MICRO lab this week. You measure 0.1035 (±0.0001) g of copper metal and dissolve it in a few mLs of concentrated nitric acid. This solution is diluted to the mark with water in a 50.00 (±0.05) mL volumetric flask. You withdraw a 5.00 (±0.01) mL aliquot with a volumetric pipet and deliver it to a 100.00 (±0.08) mL volumetric flask. After dilution to the mark with water, calculate the concentration and the absolute error in a solution of copper in ppm (assume ppm = 1 µg/g = 1 µg/mL = 1 mg/L).

1. Calculate the experimental density of a salt solution and the percent error (same as relative error percent) using some or all the data given below. solubility of NaCl salt in water: 0.357 g/mLmass of empty graduated cylinder: 25.19g mass of graduated cylinder + salt solution: 30.47g total volume of salt solution: 4.98 mLtrue density of salt solution: 1.07 g/mL

The standard solution is prepared by dissolving a known mass of zinc pellets with conc. HCl. The solution is then neutralized, transferred into a 250 mL volumetric flask and filled to the calibration mark. If 0.9809 g of Zn was weighed using an electronic balance with a relative uncertainty of ± 0.01 % and the 250 mL volumetric flask has a known relative uncertainty of ± 0.06 %, what would be the absolute uncertainty of the concentration of the solution? The molecular weight of the zinc pellets is 65.39 g/mol