# Chapter 3 Example

## Writing -rA Solely as a Function of X.

Write the rate law for the elementary liquid phase reaction

solely in terms of conversion. The feed to the batch reactor is equal molar A and B with CA0 = 2 mol/dm3 and kA= .01 (dm3/mol)41/s.

Hint 1

What is the rate law?

The reaction is elementary so what happens to the coefficients from the reaction?

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Hint 2

What is the concentration of A?

Liquid phase, v = vo (no volume change)

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Hint 3

What is the concentration of B?

What is ΘB?

Equal molar

Species A is the limiting reactant because the feed is equal molar in A and B, and two moles of B consumes 3 moles of A.

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Solution

Write the rate law for the elementary liquid phase reaction

solely in terms of conversion. The feed to the batch reactor is equal molar A and B with CA0 = 2 mol/dm3 and kA= .01 (dm3/mol)41/s.

1) Rate Law: -rA=kC3AC2B

2) Stoichiometry:

Species A

Liquid phase, v = vo (no volume change)

Species B

What is ΘB?

Species A is the limiting reactant because the feed is equal molar in A and B, and two moles of B consumes 3 moles of A.

We now have -rA=f(X) and can size reactors or determine batch reaction times.

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