Solving for best-fit variable over range of data

  • Hello, I have a set of data comprised of pressure as a function of time. This set of data follows a first-order reaction rate.


    [TABLE="width: 200"]

    [tr]


    [td]

    Pressure (atm)

    [/td]


    [td]

    time (hr)

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]0.00E+00

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    0

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]1.18E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    1

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]1.96E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    2

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]2.62E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    3

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]3.14E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    4

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]3.93E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    5

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]3.93E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    6

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]5.24E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    7

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]5.50E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    8

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]5.50E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    9

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]5.76E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    10

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]5.76E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    11

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]6.28E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    12

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]6.28E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    13

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]6.28E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    14

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]6.54E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    15

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]6.54E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    16

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]6.81E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    17

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]6.54E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    18

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]6.54E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    19

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]6.81E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    20

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]7.07E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    21

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]7.07E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    22

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]7.07E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    23

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]7.07E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    24

    [/td]


    [/tr]


    [tr]


    [td]

    [TABLE="width: 85"]

    [tr]


    [TD="class: xl65, width: 85, align: right"]7.07E-05

    [/tr][/td][tr]


    [/tr]


    [/TABLE]
    [/TD]

    [td]

    25

    [/td]


    [/tr]


    [/TABLE]


    The equation I am using to solve for P(t) is:
    P(t)=Pf * (1- exp(-k*t))
    where Pf = final pressure, which in this set of data is 7.07E-05 atm.
    I am trying to find the 'best fit' k for these data. Using goal seek would only get me the value of k for a single value of t, but I'm trying to find a k that would work the best for the entire data range. I understand there would be some error in this 'best-fit' k, as it couldn't get all of the calculated p values [P(t)] exactly as what is in the table. Any help is appreciated, thank you!

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