Chemistry Help
Hey guys I need help with this chemistry problem.
Consider the following hypothetical aqueous reaction: A-->B. A flask is charged with 0.065 mol of A in a total volume of 100.0 mL. The following data are collected:
Time (min) 0 10 20 30 40
Moles of A 0.065 0.051 0.042 0.036 0.031
Part A) By using appropriate graphs, determine whether the reaction is first order or second order.
Part B) What is the rate constant for the reaction?
Part C) What is the half-life for the reaction?
If you guys could show work I would be grateful. Thank you
May 6, 2014
3 Comments • Newest first
[quote=LowWillpower]It's actually 0th order reactions that are linear.
1st order are logarithmic.
This one is second order, but it behaves almost logarithmically too.[/quote]
Ah, that's right. Sorry, a little rusty on chem
[quote=Ness]You can tell that the reaction is 2nd order because the rate at which the concentration of A is changing with time is not [i]linear[/i]. As you can see, the change between 0 and 10 seconds is 0.14M, but the change between 10 and 20 is 0.09M.
The rate constant [i]k[/i] is obtained using the formula for second order rates, or (1/[A]) - (1/[A]o) = kt. Using values 0.65M for [A]o, 0.51M for [A], and 10 seconds for t, we find that our rate constant is 0.0422323 1/M*s
Half-lives for second order reactions are described by the equation: t = 1/(k*[A]o), so our half-life is 36.429 seconds.[/quote]
It's actually 0th order reactions that are linear.
1st order are logarithmic.
This one is second order, but it behaves almost logarithmically too.
You can tell that the reaction is 2nd order because the rate at which the concentration of A is changing with time is not [i]linear[/i]. As you can see, the change between 0 and 10 seconds is 0.14M, but the change between 10 and 20 is 0.09M.
The rate constant [i]k[/i] is obtained using the formula for second order rates, or (1/[A]) - (1/[A]o) = kt. Using values 0.65M for [A]o, 0.51M for [A], and 10 seconds for t, we find that our rate constant is 0.0422323 1/M*s
Half-lives for second order reactions are described by the equation: t = 1/(k*[A]o), so our half-life is 36.429 seconds.