標題: Order reaction [打印本頁] 作者: sam兄 時間: 2009-3-6 09:31 標題: Order reaction
Order reaction 有3 種,
zero,first 同second.
rate of reaction 既 eqn係: k[A]^m<strong>^n
k係咩既?
k既until 係 s^-1
係唔係k係 reaction per unit?
Rate of reaction 既unit有係唔係 Ms^-1
佢既M 係molarity 定係molality?
我有咩方法可以知佢地係 zero,first 定係second reaction?
thank you 作者: 大愛 時間: 2009-3-6 13:33
Indeed the order of reaction can be an integer (0,1,2,3,...) or a fraction (1/2, 3/2, etc). But in CE/AL chemistry, you will only see examples having the orders of reaction like 0, 1 or 2.
The general rate expression for a reaction A + B ---> C is
rate = k[A]^m [B]^n
k is called the rate constant. The units of k depends on the dependence of [A] and [B]. Note that the units of rate is always M/s where M is molarity. Therefore, from the dimension analysis (not sure if you have learnt this from AL Physics),
[M/s] = [k][M^m][M^n]
[k] = [1/M^(m+n-1)s]
The units of k should be M^(1-m-n) s^-1. For a first-order reaction, rate = k[A], the units of k is M^(1-1-0) s^-1 = s^-1.
The order of a reaction can be deduced from the plot of rate versus time. The zeroth, first and second-order reactions do give different types of rate-time plots. 作者: sam兄 時間: 2009-3-9 07:57
o the problem is
for me im not studying in CE or Al
it is college level in USA
and question come again
example:
2C4H6>C8H12
T=0 [A]=0.0169M
T=12.18 mins [A]=0.0144M
T=24.55 mins [A]=0.0124M
T=42.50 mins [A]=0.0103M
T=68.05 mins [A]=0.00845 M
like this kind of question
1)how can i know the order of this reaction?
For me I think it is first order.
as rate of reaction is kinda of similar
2) how can i know the rate constant k?
Thank you
um can you give me ur msn in PM?
I would like to ask you the question through msn directly
plx let me know if you can or not
thank you so much