I need these 3 labs revised. any questions, please reach out. thank you
response from lab 10 info
First, for the initial iron(III) ion and initial thiocyanate ion
concentrations, you need to show the concentrations you get after using the
M1V1 = M2V2 dilution equation for each of the tubes rather than the volumes you
used. Be sure to treat all volumes as having 3 sig figs. For
example, for the iron(III) ion concentration in Tube 1, you used 5.00 mL of
0.00200 M Fe(NO3)3 solution and diluted to a final volume of 10.0 mL. The
5.00 mL is the V1. 0.00200 M is M1. V2 = 10.0 mL. Notice how
all those numbers have 3 sig figs. Solving for M2 you get 0.00100 M for
the iron(III) concentration in Tube 1. That’s the value you should show
in the table.
It turns out the iron(III) ion concentration is the same for all the
tubes.
Calculating the thiocyanate ion concentration is a little different though
since you use a different volume in each tube. V1 is 2.00 mL in Tube
1. V1 = 3.00 mL in Tube 2. V1 is 4.00 mL for Tube 3 and it’s 5.00
mL for Tube 4.
When calculating your equilibrium concentrations, it’s probably better to
avoid scientific notation so you can see how the subtraction works. For
example, the equilibrium concentration of iron(III) in Tube 1 would be
calculated by 0.00100 M – 0.0000402 M. Since 0.00100 M has 5 decimal
places and you’re doing subtraction, the answer would be rounded to 5 decimal
places. This gives you an answer of 0.00096 M for Tube 1.
By the way, when you report numbers using exponential notation, you really
need to use standard scientific notation. In standard scientific
notation, the first part of the number needs to be at least 1 but less than
10. So rather than reporting an answer as .40 x 10^-4, you should report
it as 4.0 x 10^-5. With correct sig figs, the number should actually have
been reported as 4.02 x 10^-5.
Your Kc values were calculated correctly although the number of digits you
reported for each did not correspond to the correct number of sig figs.
You did not list the Kc values in increasing order. I’m not sure how
you determined the range and average values you reported, but once you list the
Kc values in increasing order, the range is just the highest value minus the lowest
value. You calculate the average Kc by adding the four Kc values and
dividing by 4.
You did not show a lot of the calculations you were supposed to.
Please revise your Lab 10 and re-submit it as soon as you can.