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1.11.2 Integrating standard functions

1.11.2 Integrating standard functions

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Question 53

The concentration C C\,C of a catalyst in a chemical reaction vessel, measured in mg/L, is modelled by the equation

C=1005(3t−k),t≠k3 C = \frac{100}{5(3t - k)}, \quad t \neq \frac{k}{3} C=5(3t−k)100​,t=3k​

where t t\,t is the time in seconds since the start of the reaction, k k\,k is a positive constant, and k≠3k \neq 3k=3.

a.

Find dCdt\displaystyle \frac{dC}{dt}dtdC​, giving your answer in simplest form in terms of kkk.

[3]
b.

The rate of change of the concentration at time t=1t = 1t=1 is -15 mg/L/s.

Find the two possible values of kkk.

[3]
c.

Given also that k<3k < 3k<3,

find the equation of the normal to the curve of C C\,C against t t\,t at the point where t=1t = 1t=1, writing your answer in the form at+bC+c=0at + bC + c = 0at+bC+c=0, where a,b a, b\,a,b and c c\,c are integers to be found.

[3]
d.

Show, using algebraic integration, that

∫131005(3t−k) dt=λln⁡2 \int_{1}^{3} \frac{100}{5(3t - k)} \, dt = \lambda \ln 2 ∫13​5(3t−k)100​dt=λln2

where λ \lambda\,λ is a constant to be found.

[4]
Markscheme

1.11.2 Integrating standard functions Questions

  1. A Level
  2. /Maths
  3. /1.11.2 Integrating standard functions

139 exam-style questions on AQA A Level Maths 1.11.2 Integrating standard functions. Each one has a worked solution and a mark scheme showing where the marks go.

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