ABSTRACT In the “Density, Accuracy, Precision and Graphing” experiment, the purpose was to determine the density of water and the concentration of a saline solution as well as to compare the accuracy and precision of a graduated cylinder and a graduated pipet. Based on the instructions of the lab manual, Fundamentals of Chemistry, the experiment was performed in three parts, Part A: Density of Water-The density of water was calculated by measuring the mass of three different volumes: 10mL, 30mL and 50mL. Part B: Accuracy and Precision was performed using a 100mL beaker, 10mL graduated pipet and deionized water. The experiment was performed three times; each time, 10mL of water was added to the beaker and recalculated. Part C: Density of Sodium Chloride (NaCl) Solution, a sample of NaCl was obtained and measured using a 100mL beaker and a 10mL pipet to determine the concentration of the solution.
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.
SPECIAL NOTE: For safety reasons, if you are more than 15 minutes late to prelab lecture or you completely miss a shorter lecture, you may not perform the experiment. Please ask the lab coordinator if a make-up lab is possible. Aug.27-Sept.1 Orientation, check-in. Wash glassware and watch films on safety and using standard equipment. Sept. 3 Labor Day (No labs.
Spring 2012: Art 111-09 Art Appreciation (MW 4:00-5:15 in Porterfield 208) Instructor: Steve Arbury (sarbury@radford.edu or 831-5921 or the textbook website) Office: Covington 176 Office Hours: Mon & Weds 3:30-4:00 or by appointment TEXTING IS NOT PERMITTED IN CLASS UNDER ANY CIRCUMSTANCE. Required Text: About Art (3rd revised printing). Kendall/Hunt Publishing, 2012. Make sure you purchase a new copy. (If you purchase a used copy, the code that you need to access the textbook website will not be valid.)
Also include any observations that you made over the course of part II. (4 points) Unknown (A,B,C,D) Mass of Metal Volume of water Initial temp. in calorimeter Initial temp. in beaker Final temp. of mixture Metal C 25.605g 24.6mL 25.2°C 100.5°C 28.7°C Calculations: Show your work and write a short explanation with each calculation.
(4 points) n = 125 4. If magnesium was the limiting reactant in this lab, calculate the theoretical yield of the gaseous product. Show all steps of your calculation. (4 points) Moles of Mg: (0.0281 g)(1 mole / 24.305 g) = 1.156 x 10^-3 moles 5. Determine the percent yield of this reaction, showing all steps of your calculation.
From your three trials, calculate the average volume of Na2S2O3 needed for the titration of 25.00mL of diluted bleach. 3. Use the average volume and the molarity of Na2S2O3 to determine the molarity of the diluted bleach. (Find moles of Na2S2O3, convert to moles of NaClO, and divide by volume of dilute bleach that was titrated in each trial to get M). 4.
Repeat the titration until there are two titres within 0.1cm3 of each other. Record results in a suitable table. Results: Rough Titre: 7.653 First Run: 6.553 Second Run: 6.453 Third Run: 6.553 Calculations: During the titration, iron(II) ions are oxidised to iron(III) ions and manganate(VII) ions are reduced to manganese(II) ions. The equation is as follows: 5Fe2+(aq) + MnO4-(aq) + 8H+(aq) ? 5Fe3+(aq) + Mn2+(aq) + 4H2O(l) The above equation shows that one mole of manganate(VII) ions reacts with 5 moles of iron(II) ions in acid solution.
The following data were obtained when a sample of barium chloride hydrate was analyzed as described in the Procedure section. Calculate (a) the mass of the hydrate, (b) the mass of water lost during heating, and (c) the percent water in the hydrate. Mass of empty test tube 18.42 g Mass of test tube and hydrate (before heating) 20.75 g Mass of test tube and anhydrous salt (after heating) 20.41 g. Mass of the Hydrate is 2.33g. Loss (H2O) is 0.34g. Percent H2O in Hydrate is equal 0.34/2.33=14.6% 3.
| | | An Activity Series 1/9/13 Makieya DunhamPartners: Jasmine Lewis and Danielle Anderson | | | Problem Statement: In this lab we determined the activity series for five metals and for three halogens. In the first part of the lab we used a microscale technique to rank the metals that reacted with the other metal nitrates from most reactive to least reactive. The metal that reacts with another metal nitrate, then the solid metal have reduced the other metal ion and is the more reactive metal of the two. In the second part of the lab we used the solvent extraction technique to derive an activity series for the halogens. Safety Precautions: When in the lab we wore goggles, an apron, and gloves the entire time.