CHEM 353 Study Guide - Midterm Guide: Alkane, Formaldehyde, Alkene

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turquoisegnu128

9 Jan 2019

School

University of Calgary

Department

Chemistry

Course

CHEM 353

Professor

All

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Document Summary

Enter version number 1 on the computer answer sheet. The exam consists of parts 1 - 7, each of which should be attempted. Parts provide you with a choice of questions, e. g. answer any 5 out of 6. These will be graded in numerical order until the required number have been completed, regardless of whether they are right or wrong. Parts 1 - 4 will be computer graded, and parts 5, 6 and 7 are to be answered in the booklet provided. A periodic table with atomic numbers and atomic weights and spectroscopic data tables are included with this examination paper. Parts 1 - 4 consist of a series of multiple choice questions numbered 1 - 34 which are to be answered on the computer answer sheet. Indicate your answer by blackening out the appropriate space, a, b, c, d or e on the answer sheet. Use a soft pencil only and not ink.

Related Questions

Please answer each question, the questions have multiple parts.

I need help with question 2

Lab 5. Determination of iron in a supplement tablet by atomic Prelab Helpful Reading: Discussion of atomic absorption spectrometry: The introduction to Chapter 21, section 21-1 and the part describing flames at the beginning of section 21-2 In this lab a flame atomic absorption spectrometer will be used to determine the amount of Fe in a vitamin pill. You may select your sample from one of the pills containing -9 mg/pil, Women's spectrometer detects following three types of pills: Energy Vitamin s Vitamin pills containing 18 mg/pill. The atomic absorption Fe well when the Fe concentration is between 1.25ppm and 5ppm Answer the following prelab questions: 1. A. How will you prepare your calibration solutions? You will use five calibration solutions in this lab, including the blank. A stock iron solution for atomic absorption spectroscopy will be made available to you that has a concentration of 1000 ppm (w/v) Fe. For an iron analysis the Varian atomic absorption spectrometer in the quant lab-requires samples with concentrations between 1.25 and 5 ppm (w/v) and a blank. You will prepare 5 calibration solutions, having respectively, the following final concentrations of Fe: 0, 1.25, 2.5, 3.5 and 5 ppm (w/v) Fe. These solutions will be prepared by diluting an appropriate number of microliters of 1000ppm (w/v) Fe with DI water in a 100 ml volumetric flask. Calculate how many microliters of stock iron solution are needed to prepare calibration solutions at the concentrations mentioned above. 2. How will you prepare your sample for analysis? Draw up one experimental plan for diluting your chosen pill to an appropriate concentration for the atomic absorption instrument using a micropipette. Specifically a. Which pill, from the two types mentioned above do you propose to analyze? How many mg of Fe is the pill expected to have? Assume that you will digest a vitamin pill as you did last week, and will dilute the digest to 100ml-this solution will be called vitamin solution 1 (VS1). You willuse a micropipette to transfer some liquid from VS1 to another 100mL volumetric flask and b. will ilute this to the mark. This second solution, vitamin solution 2 (VS2) will be the sample that you measure. What volume should be transferred from sample solution 1 to sample solution 2 with the micropipette? Draw a picture to illustrate your dilution scheme. Write out a sample preparation equation relating the estimated concentration in the mg/pll (based on the label) to the estimated concentration (in units of ppm) of Fe in the sample that will be measured. Do this in your lab notebook. c. d. Lab 5 Determination of iron/atomic absorption spectroscopy 31

GRAPHING EXERCISE #1

Graph the following data on one graph using Excel.

The following data was obtained in a lab exercise comparing temperature and gas pressure. The quantity and the volume of the gas were constant.

Temperature in ÂºC	Pressure in mm Hg
100	1174
73	1079
52	1020
25	949
0	861
-30	758
-48	700
-79	601
-94	566
-100	500

Plotting Graphs Using Excel

1. Click on the Excel icon. A series of rows and columns will appear.

Column A corresponds to the x-axis and Column B corresponds to the y-axis.

Enter the values for the x- and y- axes in columns A and B, respectively.

Position the cursor on the first cell, click and hold down the left mouse button and highlight all the values of columns A and B you have entered.

Click on the chart wizard (an icon that looks like a bar graph).

Click on scatter, next, and then click on the second sub choice. Click on next.

Click on next.

Your graph should show up on the screen. Click on next.

Click on chart title. Type in the title of your graph followed âby your nameâ. Label the x- and y-axes by placing a name with units in the space given for Category x and Value y.

Click on gridlines. Click on minor gridlines for both the x- and y-axes. Click on next.

You are given a choice between saving as a new sheet or saving in the current sheet. Saving as a new sheet will produce a larger picture of the graph, while saving within the current sheet allows for both the data sheet and graph to be printed on the same page. Click as a new sheet and the click finish.

If there is a lot of empty space on your graph, you need to adjust the scale on the x- and y-axes. To do this, double click on the axis you wish to adjust. The number that you will be changing appears in the âminimumâ box. (Note: the value at the origin does not necessarily need to be zero.

To print the graph, click on file and then click on print.

GRAPHING EXERCISE #2

Use this data in the following exercises.

Time, min Mass, g Time, min Mass,g

0.0 8.860 6.0 8.765

1.0 8.844 7.0 8.748

2.0 8.828 8.0 8.734

3.0 8.814 9.0 8.719

4.0 8.796 10.0 8.703

5.0 8.782

1. Using Excel, graph the time and mass data as in #1. Using the linear regression feature on excel, determine the equation of a line and show that equation on your graph.

2. Answer the following questions using the graph you have created above.

What is the independent variable?

What item is plotted on the abscissa?

What would be the mass of acetone in grams at a time of 12 minutes?

What would be the mass of acetone in grams at a time of 4.6 minutes? Show two ways to find this value.

CHEM 353 Study Guide - Midterm Guide: Alkane, Formaldehyde, Alkene

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