In ismayc/chemistr: Facilitates use of R functions and R Markdown files for Chemistry lab reports

library(chemistr)

Results

#Raw Data 

Time <- c()  #Elapsed time at count start in seconds
Raw_Counts <- c()  #Counts obtained from the radiation detector in units of decays per 10 seconds
Background <- c()  #Background counts in 10 seconds
Avg_Background <-   #calculate the average background counts
Counts <-     #Subtract the background counts off of the raw counts
Ln_A <-    #Calculate the ln of counts.  Note natural log (ln) in R code is log().

Data <- data.frame(Time, Raw_Counts, Counts, Ln_A)

#Graph of Complete Data.  Graph the data as ln(A) versus time.  The total counts will be from both nuclides.  Therefore it will be necessary to interpret the data for each individual nuclide. You should notice that the plot has two regions of linearity to it - one for each nuclide.  Therefore it does not make sense to fit the data to a straight line yet (aka in the chem_scatter function, include reg_line = FALSE)

#in your caption make sure it is clear what you are testing and how the data was obtained.  Also include why the graph is ln(A) versus time and not A vs time or 1/[A] vs time.  What does this tell us about the kinetics of nuclide decay?

chem_scatter()

#Graph of longer lived Ag nuclide.  Look at the graph above and determine where the longer lived nuclide (end of your graph) is no longer linear. This should be around 300 seconds.  The best fit line will extrapolate back the activity in the earlier data points that are due to the longer lived Ag nuclide.

#In your caption make sure you identify the nuclide and report the half-life +/- the standard error (aka uncertainty) of this nucloetide based off of the graphical fit to the data.

long_data <- subset(Data, Time >= 300)  #This code will allow you to only select a subset of your values in Table 1.  This is important in making sure you are trying to fit only the longer lived nuclide data.

chem_scatter(long_data, Time, Ln_A, xlab = "Insert Label", ylab= "Insert Label")

fit1 <- lm(Ln_A ~ Time, data = long_data) #remember to view the values from this, you must type summary(fit1) into the console.

slope<-summary(fit1)$coef[[2]] #This creates a variable for the slope

Intercept<-summary(fit1)$coef[[1]] #This creates a variable for the intercept

#Graph of the shorter lived nuclide (~ t < 300 seconds).

#Calculate the amount of activity in the early time points (~ t < 300 seconds) that is due to the longer lived nuclide. This is done by fiting these time points into the best fit line of the graph above.

#In your caption make sure you identify the nuclide and report the half-life +/- the standard error (aka uncertainty) of this nucloetide based off of the graphical fit to the data.

short_data <- subset(Data, Time <= 300)  #This code will allow you to only select a subset of your values in Table 1.  This is important in making sure you are trying to fit only the shorter lived nuclide data.

short_data$ln_A_Long <-   #Calculate the amount of ln(activity) in the early time points (~ t < 300 seconds) that is due to the longer lived nuclide. This is done by fiting these time points into the best fit line of the graph above.  Example: short_data$Time*Slope+Intercept would give you the the natural log of the counts due to isoptope B.  The format data_frame$New_variable is a way to add a column to a data frame.  It is also a way to reference a column in a data frame if you haven't specified it separately.

short_data$A_long <- exp(short_data$ln_A_Long) #This converts the ln(A) back into counts due to the long-lived nuclide.

short_data$A_Short <-   #subtract the long lived nuclide, short_data$A_long from the total Counts (variable for this is short_data$Counts) to get the counts due to the shorter half-life.

short_data$ln_A_Short <- log(short_data$A_Short) #ln(A) for short lived nuclide

chem_scatter(short_data, Time, ln_A_Short, xlab = "Insert Label", ylab= "Insert Label")

fit2 <- lm(ln_A_Short ~ Time, data = short_data) #remember to view the values from this, you must type summary(fit2) into the console.

Discussion (Answer the following questions)

Short-Lived Ag Nuclide

1. What is the identity of the short-lived silver nuclide?

2. What is the literature value for this nuclide's half-life? (Include a citation)

3. What is the experimental value for this nuclide's half-life? (Report the uncertainty too).

4. Is the experimental value accurate? Explain the evidence that supports this statement.

Long-lived Ag Nuclide

1. What is the identity of the long-lived silver nuclide?

2. What is the literature value for this nuclide's half-life? (Include a citation)

3. What is the experimental value for this nuclide's half-life? (Report the uncertainty too).

4. Is the experimental value accurate? Explain the evidence that supports this statement.

ismayc/chemistr documentation built on Feb. 4, 2023, 12:44 p.m.