Pb (NO3) 2 10. A compound is 42.3 % C, 5.94 % H, 32.9 % N, and 18.8 % O and has a molecular mass of 425.25 g/mol. Calculate the empirical and molecular formula. C15H25N10O5 11. How many moles of Al2O3 are produced by the reaction 200. g Al?
Nest one Styrofoam cup in another 11. Obtain an exact mass of tap water (45-50g) to serve as cold water 12. Put a magnetic stirrer in the bottom of the calorimeter 13. Secure temperature probe to a ring stand 14. Place temperature probe through hole in cardboard lid and position probe about 1cm above bottom of calorimeter 15.
* Trial 1 36-25.5=10g * Trial 2 36-25=11g * Trial 3 35.5-25=10g 2. Calculate the density of the unknown liquid for each trial. (Divide the mass of the liquid calculated above by the volume of the liquid.) * Trial 1: 10.5/50=0.20g/mL * Trial 2: 11/49=0.20 g/mL
In the first part, five 100 mL flasks of 5 mL ligand solution, 5 mL 2 M sodium acetate, 4 mL 3 M NH2OH, and 1-5 mL Fe2+ solution are diluted with water. The absorption spectrum for varying concentrations of Fe2+ are measured using a spectrophotometer and the data is graphed in Excel. The slope of the line is ε in the Beer-Lambart equation A = εcl. In the second part of the experiment, eleven flasks containing diluted stock solutions of Fe2+ and ligand are mixed with 5 mL 2 M sodium acetate and 4 mL 3 M NH2OH and diluted with water. The absorption spectrum is measured using a spectrophotometer and the data is graphed in Excel.
Methods and Materials - Place 1.33g NaBr, 1.5 ml of water and 20 drops of 1-butanol to a 5-ml round bottom long-necked flask and set a distillation apparatus. Add 22 drops of concentrated H2SO4 and reflux for 55 minutes. For more details about the procedure and how to set the simple distillation apparatus check the book pages 312 to 314. IV. Results - After transferring the distillate to a reaction group the halide form the top layer.
Determining the mass of the two unknown weights (unknown weight #1 and #2) was determined using only the centigram balance using the weighing by difference method. Unknown weight # 1 had a mass of 24.82 g while unknown weight #2 had a mass of 25.17 g. The average mass experiment was conducted by individually weighing five different copper slugs on an electronic balance, then
K12_1821161 $500 Answer from 3 Jan 9, 2014 1:03:23 PM Page 34. Blackboard Collaborate ?? K12_1821161 $100 Question from 4 Jan 9, 2014 1:03:23 PM Page 35. Blackboard Collaborate ?? K12_1821161 $100 Answer from 4 Jan 9, 2014 1:03:23 PM Page 36.
Grace Murphy 15 September 2015 7th Hour Katelyn Stevens Determine the Density of Aluminum Purpose: To determine the density of aluminum using the water displacement method. Procedure: First, fill a 10 mL-graduated cylinder as close to 5 mL as possible with water and record the volume ( to the nearest 0.01mL) on the data sheet. Next, find the mass of the container with the aluminum using a balance and record it on your sheet. Carefully drop pieces of the aluminum into the graduated cylinder. Drop just enough pieces to rise the water level 0.5 mL.
Find mass of CaCO3 after 5 minutes 4. Find the difference in mass between CaCO3 and CO2 5. Repeat 1-4 for NaHCO3 6. Repeat 1-4 for CuCO3 Results: | 1st trial | 2nd trial | 3rd trial | CuCO3 | 17.85 | 17.8 | 17.84 | CO2 emission | .25g | .3g | .26g | NaHCO3 | 17.35 | 17.5 | 17.65 | CO2 emission | .6g | .75g | 4.5 | CaCO3 | 18.1 | 18.05 | No results | CO2 emission | 0 | .5g | No results | Percent yields: Compound | Actual | Theoretical | Percent | CaCO3 | .25 | .44 | 57% | CuCO3 | .27 | .35 | 77% | NaCO3 | .6 | .31 | 198% | zConclusion: My hypothesis was not correct according to my results. I had based my hypothesis off of the theoretical yield data we collected after doing a few stoichiometry equations.
Q = Mc Cc ΔT (2) Where Cc = 0.215 cal/(g °C) A nylon cord is wound five times around the aluminum calorimeter. The frictional force between the band and the calorimeter is large enough that one end of the band can lift a 10 kg weight while the other end becomes slack. As a result of this mechanical trick, the frictional force is equal to the weight of the 10 kg mass and is to a large extent independent of the speed at which the drum is rotated. The work of friction (Wf) is