02_NuclearChemistry_PostLab_Spr24

docx

School

Arizona State University *

*We aren’t endorsed by this school

Course

116

Subject

Chemistry

Date

Apr 3, 2024

Type

docx

Pages

Uploaded by DeaconHeatPigeon19

Nuclear Chemistry Scarlet Roberts 3/18/2024 TOTAL: 30 points

Insert Last Name Estimating Half-Life Page 2 of 13 CHM 116 POST-LAB and LAB NOTEBOOK Nuclear Chemistry: Estimating Half Life of a “Radioactive” Element 1. Insert ONE picture of yourself in the appropriate lab attire and full PPE here ( include the Skittles® candy in your PPE picture ). **Remember to (1) show your full body so that we see you are wearing shoes; (2) wear your PPE (safety glasses, buttoned lab coat and gloves); (3) cover your lower legs and ankles (socks are required, even in Arizona); (4) tie back long hair in a ponytail or a bun; (5) remove jewelry. Note: Wearing full PPE may seem silly for tossing Skittles on a table, but we are establishing good lab protocol. If you have not received your lab kit (which contains your safety glasses), take the picture with what you have and include a note with your picture to explain why you are not wearing the complete PPE. I didn’t have q lab coat but used what I could. It was rather hard to find a affordable lab coat for my tests.

Insert Last Name Estimating Half-Life Page 3 of 13 2. Enter the data that you collected during the experiment (from Tables 1 and 2 in the procedure) HERE. Remember to adjust the number of Rounds for each Trial to how many you completed . Table 1 (Trial 1) Table 2 (Trial 2) Roun d Skittles “S” Up (Parent Atoms) Skittles “S” Down (Daughter Atoms) Cumulative Daughter Atoms Round Skittles “S” Up (Parent Atoms) Skittles “S” Down (Daughter Atoms) Cumulative Daughter Atoms 0 60 0 0 0 60 0 0 1 26 34 34 1 34 26 26 2 14 20 20 2 10 16 16 3 4 16 16 3 5 11 11 4 5 11 11 4 2 9 9 5 1 10 10 5 1 8 8 6 4 6 6 6 3 5 5 7 2 4 4 7 4 1 1 8 3 1 1 8 9 9 10 10 3. Describe , in 2 - 3 sentences , what happens mathematically to the total number of candies in each round (the general trend)? How is this related to the concept of half-life in nuclear reactions ( or, what is each round simulating with regards to half-life )? 4. Are your two data sets exactly the same? If not, explain (in 1 – 2 sentences) using your experimental data. With the first trial the half-life of the parent atom is independent. and in each round the number of parent atoms left will form the daughter atoms. The half- life of both trials is different but the same at the same time. For each trial it is up to how you throw the skittles that will depend on the amount of each test/ experiment that will ultimately decide the next generation. So, they will decrease over time. Until it is completely empty.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Insert Last Name Estimating Half-Life Page 4 of 13 5. Use a graphing software to create the x-y scatter plot showing the Number of parent nuclei remaining vs. Round # (do not connect your points). Your ONE graph will show data points from BOTH trials of the experiment . On your graph, the x-axis should be Round Number , and the y-axis should be Parent Atoms Remaining ( NOT the daughter atoms or cumulative daughter atoms ) in that Round. In general, scientific graphs show the independent variable on the x-axis and the dependent variable on the y-axis. Do NOT connect your points; no trend line needed and m ake sure to:  Label the axes including the units in parentheses.  Include a figure legend (text below the graph) explaining the data in your graph.  Remove any default title, legend, and gridlines.  You should use two different symbols to represent the two data sets (i.e. a square for Trial 1 and a circle for Trial 2) You will not receive credit if you draw your graph by hand. Excel or Google Sheets are good choices that you can learn how to use quickly if you don’t already have a favorite graphing program. See other general tips for making graphs in the How to Make a Graph in Excel document located in the Introductory Materials for this lab. 6. Consider the trend shown in your graph in Question 5. Is it linear, exponential growth or exponential decay ? Is this trend consistent with your expectations for the kinetics of a nuclear reaction? Briefly explain why in 2 – 3 sentences. 0 1 2 3 4 5 6 7 8 9 0 10 20 30 40 50 60 70 skittles trial 1 and 2 decay skittles 'S skittle 's daughter atoms round *** skittles 's skittles daughter atom*** rounds parent The trend of my graph shows an exponential decay. What is being shown is that the half-life of the parenting atom is decreasing as you do each test/ trial. Which would show a decrease within the graph.

Insert Last Name Estimating Half-Life Page 5 of 13 7. Scientists like to use data to build physical models (or mathematical models to predict how data will look). Linear trends are easiest to work with; so we often look for ways to identify linear trends in a data set. Nuclear reactions all follow first order kinetics meaning the rate of a nuclear reaction is given by: rate = k [ radioactiveisotope ] in which k is a first order rate constant. As shown in the kinetics portion of this course, this relationship can be transformed to the following integrated rate law : ln [ radioactiveisotope ] t =− kt + ln [ radioactiveisotope ] 0 Equation 1 in which ln is a natural logarithm, t is time (represented by the Round number in your experiment), [radioactive isotope] 0 is the concentration at time zero (the number of Skittles you start with in this experiment) and [radioactive isotope] t is the concentration of radioactive isotope at time t (number of remaining parent Skittles in this experiment). We need to adjust our data to create a graph which represents the above linear equation for first order kinetics. For each round in your experiment, calculate the natural log (ln) of the number of Parent atoms ( you are NOT using the above equation to find this value; just use the ln button on your calculator or create an equation in Excel ). Enter the Round number and number of Parent Atoms Remaining (from Tables 1 and 2 in Question #2), and ln(Parent Atoms) in Table 3 below: Table 3 : ln(Parent Atoms) vs. Round number Trial 1 Trial 2 Round Skittles “S” Up (Parent Atoms) ln (Parent Atoms) Round Skittles “S” Up (Parent Atoms) ln (Parent Atoms) 0 60 1.78 0 60 1.78 1 26 1.41 1 34 1.53 2 14 1.15 2 10 1 3 4 0.60 3 5 0.70 4 5 0.70 4 2 0.30 5 1 0 5 1 0 6 4 0.60 6 3 0.48 7 2 0.30 7 4 0.60 8 3 0.48 8 9 9 10 10

Insert Last Name Estimating Half-Life Page 6 of 13 8. Consider the data in Question 7 and create a new graph of your data showing a linear relationship between Round Number (x-axis) and Natural Log of Concentration of Parent Atoms (y-axis) . You will want to exclude Rounds where # of Parent atoms is ZERO from each trial . Draw a trend line (OR straight line of best fit) through each set of data points. (Include the equations of both trend lines and the R 2 values in the figure legend below the graph. These will be provided by Excel).  Label the axes including the units in parentheses.  Include a figure legend (text below the graph) explaining the data in your graph.  Remove any default title, legend, and gridlines.  You should use two different symbols to represent the two data sets (i.e. a square for Trial 1 and a circle for Trial 2) See other general tips for making graphs in the How to Make a Graph in Excel document located in the Introductory Materials for this lab. 0 1 2 3 4 5 6 7 8 9 0 10 20 30 40 50 60 70 f(x) = 31.83 exp( − 0.46 x ) f(x) = − 5.38 x + 34.76 parent atoms vs round trial 1 skitl;es Linear (trial 1 skitl;es ) In(parents) round*** trial 2skittles Exponential (trial 2skittles ) In(parent)*** rounds parent atoms trial 1 and 2 Insert Graph Here

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Insert Last Name Estimating Half-Life Page 7 of 13 9. Consider the trend lines in Question 8 and answer the following questions. a. What are the equations for your trend lines for Trial 1 and Trial 2? (graphing program will provide this) b. In regard to the integrated rate law (see Equation 1 in Question 7) for a nuclear reaction, what do the slopes of the trendlines in your graph represent ? c. In regard to the integrated rate law (see Equation 1 in Question 7) for a nuclear reaction, what does the y-intercept represent ? 10. Consider the following data for an experiment similar to the one you conducted with Skittles. Round Skittles “S” Up (Parent Atoms) Skittles “S” Down (Daughter Atoms) 0 100 0 1 55 45 2 24 31 3 12 12 4 5 7 5 3 2 6 1 2 7 0 1 a. How many Rounds (cycles of decay) does it take for 100 Skittles to “decay” according to the above data for this experiment? b. Now consider repeating the same experiment, but instead starting with a sample of twice the size (200 Skittles). How many cycles of decay would you predict it Trial 1: Trial 2: Slope represents (k) the rate of constant The y intercept represents the A or radioactive isotope. # of cycles for 100 Skittles 7 cycles

K=In(2)/t1/2=0.693/12.7 hours=0.0545h^-1 K=In(2)/t1/2 In(2)=0.693 (e^-0.0545*38.0)*100=0.126*100=12.6% after 38.0 hours,12.6% of the original activity of 64 Cu remains. Insert Last Name Estimating Half-Life Page 8 of 13 would take for your entire sample to decay completely? Explain your answer in 2 – 3 sentences. 11. Putting it all together! Radioisotopes are often used in diagnostic imaging for detecting disease. The isotope 64 Cu (copper-64), which has a half-life of 12.7 hours, is used to study diseases affecting copper metabolism such as Wilson’s disease. What percentage of the original activity in the sample remains after 38.0 hours? Show your work, include units, and pay attention to significant figures. Hint: Remember that this process follows first order kinetics and that half-life is given by: k = 0.693 t 1 2 # of cycles for 200 Skittles: 14 rounds Explain: I would assume that it would take 14 rounds as there is double the number of skittles to throw over time for each test. But I could be wrong since it is a 50/50 chance there would be more or less needed to the original amounts shown above. Leading to only needing possibly one or two more rounds instead of double the amount rounds.

Insert Last Name Estimating Half-Life Page 9 of 13 116 Online Lab Notebook Entry ( 5 Points) Purpose/Goal of Experiment: the purpose of this lab is to determine the half life of each round until it is empty or gone. And then compare and contrast your results in graph form with a second trial. Then give a explanation as to why you came to a conclusion. Planned Observations: at first, I was just thinking it was to do with graphing your findings and comparing your results. But as I went through I realized it was more of understanding your results with regards to half life of atoms and how they function. Experiment Title: nuclear chemistry post lab and lab notebook. Date of Experiment: 3/18/2024 Student Name: Scarlet Roberts

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Insert Last Name Estimating Half-Life Page 10 of 13 Qualitative/ Quantitative Observations: overall my understanding of half life within the experiment meant that using the 50/50 chance method of tossing the skittles and removing the ones that are either heads down each round meant that the half life of that round was reduced and then what ever was left over would be used again to do another round and what ever again was heads down in the next round would be taken out again until their was nothing left to toss. graphing on the other hand is a bit challenging but I did what I could in regards to what type of graph was asked of me.

Insert Last Name Estimating Half-Life Page 11 of 13 Data/Calculations: I used my calculator and Excel to help me plan out my calculations. the excel sheet helped plan out where to put my points of my graph and the calculator was in use when calculating how many skittles were “s” side up and how many were “s” side down. And once I got to my second graph is when I needed it to input my parent atoms to find my Log (parent atoms). So, most of my calculations are from excel and my calculator.

Insert Last Name Estimating Half-Life Page 12 of 13 Conclusion: half life is like a game of 50/50 and can change over each round until it is completely empty. And determining your results for graphing is based off what you get each round. So each test isn’t going to be the same but the end results are some what the same over time and if graphed correctly.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Insert Last Name Estimating Half-Life Page 13 of 13

02_NuclearChemistry_PostLab_Spr24

Related Documents