P1 S1 Lab Report
Data P1: https://www.sendspace.com/file/xuw4bv
Data P2: https://www.sendspace.com/file/wrfzva
Data P3: https://www.sendspace.com/file/aqxu6g
Read and follow the guide.
P1 Guide: https://www.sendspace.com/file/d98k0t
Write the report in “P1 S1 Lab Report” form.
P1 S1 Lab Report: https://www.sendspace.com/file/6krsfo
P1 S1 Pre-Lab Worksheet: https://www.sendspace.com/file/w9qvij
P1 Task 2 Excel: https://www.sendspace.com/file/ckoebt
Don’t use outside sources.
Answer all questions.
Note: you can download the file from “sendspace”.
All work must be well-written and organized. If your penmanship is poor, you must type all responses. If you need to organize your thoughts, please use a separate sheet of paper. A major objective of this lab course is to develop skills in scientific communication. Just having the right “answer” is not good enough – you must communicate clearly and succinctly and use terms and concepts correctly. When typing, all sections must have a line spacing of 1.5 to give room for TA feedback (the document is set to this spacing).
Task 1 Results Table (5 p) Using the table you prepared for Question 1 of the Pre-Lab Worksheet as a starting point, correct the table (if necessary) so that only the actual volumes and ratios prepared appear. Expand the table to include the observed color changes and temperature data. Remember, tables must always be very well-organized, property titled/labeled and have entries with the correct units and sig figs.
Task 2 Beer’s Law Calculation (8 p). State the mathematical formula used to calculate the equilibrium concentration (Ceq) defining all variables and constants. Then give one example calculation. Be certain you have the correct sig figs and units.
Task 2 Results Table (7 p) Prepare a table of equilibrium constant Kc results for the various CoCl2(Alc)2/MeOH ratios at room temperature.
Task 2 Analysis (16 p) Examine your Kc values for any trends. Relating your Tasks 1 results, discuss chemically, what possible mechanism(s) could account for your observed Kc values. Your response must be well-written, in full sentences, and must use terms and concepts correctly.
Task 2 Errors Analysis (4 p) Aside from “human error”, identify two major sources of error in Task 2.
Project 1, Session 1
Pre-Lab Worksheet
All work must be well-written and organized. If your penmanship is poor, you must type all responses. If you need to organize your thoughts, please use a separate sheet of paper. A major objective of this lab course is to develop skills in scientific communication. Just having the right “answer” is not good enough – you must communicate clearly and succinctly and use terms and concepts correctly.
Question 1 (4 p) Task 1 concerns exploring the thermochromic behavior of cobalt alcohol solutions (CoCl2(Alc)2) with methanol (MeOH). You are to prepare CoCl2(EtOH)2/MeOH and CoCl2(iPrOH)2/MeOH in ratios between 2:1 to 4:1 and observe the color at room temperature and when placed on ice. The total volume of each prepared ratio must be 3.00 mL (this needs to be consistent). Construct a table for 4-5 ratios that clearly indicates what will be prepared and the actual volumes of the cobalt alcohol solution and methanol needed to achieve each ratio to give a total volume of 3.00 mL for:
1) CoCl2(EtOH)2/MeOH
2) CoCl2(iPrOH)2/MeOH
The table must be well-organized, property titled/labeled and have entries with the correct units and reasonable sig figs.
Table 1: exploring the thermochromic behavior of cobalt alcohol solutions (CoCl2(Alc)2) with methanol (MeOH)
Experiments Initial conc CoCl2(Alc)2 Initial Conc.
MeOH Equilibrium CoCl2(EtOH)2/MeOH Equilibrium CoCl2(iPrOH)2/MeOH Kc
1
2
3
4
Question 2 (4 p) If you add MeOH to CoCl2(Alc)2, the CoCl2(Alc)2 concentration will change. What are the two reasons for this concentration change?
i. One of the possible reasons for the change in the concentration of CoCl2 (Alc)2 that occurs when MeOH is added to CoCl2(Alc)2 is that the equilibrium of the equation shifts to the right thereby resulting in the reduction of the concentration of CoCl2 (Alc)2 as more ions move from the reactants to the product side. For example, the reaction between MeOH and CoCl2(Alc)2 will result in the formation of CoCl2(MeOH)4. Ions from CoCl2(Alc)2will be used in the reaction leading to decreased concentration of the reactants.
ii. Another possible reason for the concentration change is the removal of the Alc part of the CoCl2(Alc)2 during the reaction thereby leading to a reduction in the concentration of the reactant. For example, as shown in the equation below, two parts of Alc is removed from CoCl2(Alc)2 during the reaction:
Question 3 (2 p) To find the equilibrium concentrations for Task 2, what are you going to measure (NOT calculate)? What instrument(s) will you use?
In order to find the equilibrium concentrations for Task 2, the key thing I’m going to measure is the equilibrium constant of the Kc for CoCl2(EtOH)2 and CoCl2(iPrOH)2 (at room temperature) with MeOH reacted at various ratios.