# F325 Module 1: Summary

A summary of all the notes required for module one. Each specification point with relevant information regarding it.

- Created by: Ryan janjuha
- Created on: 10-11-12 14:05

First 362 words of the document:

Chemistry Module one of Unit 2. A2 Level.

Module 1: Chemistry

>Measuring the Rate of Reaction from a CONCENTRATION-TIME graph

Rate of Reaction = Change in Concentration / Time for the change to take place

Find a tangent to the graph at the given point, and work out the gradient.

This is the rate of reaction at that time.

>Explain and use the terms `Order' and `Rate Constant'

The Order with respect to a reactant is the power to which the concentration of the reactant is raised

in the rate equation.

Rate = k[A]^x

X= Is the Order with respect to A

There are 3 orders we need to understand:

-Zero Order: Rate = k[A]^0 Anything to power of 0 = 1

The rate is Unaffected by changing the concentration of A

-First Order: Rate = k[B]1

This outlines that if [B] increase by 2 times, then the rate of reaction will increase by 2

times etc.

-Second Order: Rate = k[C]2

If [C] increases by 2 times, then the rate increases by 2^2 times. Similarly if [C] increased by

10 times then the rate would increase by 10^2 times.

The Rate Constant, K is the constant that links the rate of reaction with the concentrations of the

reactants raised to the powers of their orders in the rate equation.

Rate = K[B]^1[C]2

The Overall Order can be found by adding the powers of order together e.g. The above rate

equation has an overall order of: 1 + 2 = 3. Also you must remember that the rate equation can be

determined only from experimental results.

Units of Rate Constants:

The units can be worked out by making K the subject in the rate equation:

E.g. for first order Rate = K[A] therefore K = Rate / [A]

Units for K are therefore moldm-3 s-1 / moldm-3 which gives s-1

Always write the units from positive to negative e.g. A third order, Rate = K[A]^2[B]^1 therefore K =

moldm-3 s-1 / (moldm-3 x moldm-3) x (moldm-3)which gives: dm6mol-2 s-1.

By Ryan Janjuha 2012

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