4- Rate Laws and Stoichiometry_stu

Today’s Lecture• Block 1: Mole Balances (Review)

Size CSTRs and PFRs given –rA=f(X)

Conversion for Reactors in Series• Block 2: Rate Laws

Reaction Orders

Arrhenius Equation

Activation Energy

Effect of Temperature • Block 3: Stoichiometry Stoichiometric Table Definitions of Concentration Calculate the Equilibrium Conversion, Xe

Review of Mole Balances

Review of Conversion

A general reaction:

fedA moles

reactedA moles X

D a

d C

a

c B

a

b A

ncalculatio of basis asA reactant limiting Choose

D d C c B b A a

Levenspiel Plot (Review)

FA 0

rA

X

CSTR(Review)

FA 0

rA

X

Area = Volume of CSTR

X1

V FA 0

rA

X1

X1

PFR(Review)

FA 0

rA

Area = Volume of PFR

V 0

X1FA 0

rA

dX

X1

Reactors in Series (Review)

Two steps to get                   

Step 1: Rate Law

Step 2: Stoichiometry

Step 3: Combine to get

rA f X

rA g Ci

Ci h X

rA f X

1010

Collision Theory

When one substance is mixed with another, the two substances ….

According to collision theory, atoms, ions, and molecules can react to form ...

Rates of chemical reactions are often measured as ...

1515

The factors that affect how ...

1616

Factors influencing the likelyhood of a reaction occurring:

1)

1717

2)

1818

3)

1919

2020

2121

2222

In order for the reaction to occur, the particles involved must collide with each other, …………………………………………………………. Not every collision results in a reaction.

activated complex

The …………………is the temporary arrangement of atoms as they change from reactants into products.

2323

Orientation

2424

The colliding molecules must have enough energy to react and form an ……………. This minimum amount of energy is called the …………..

activation energy

2525

Rate of a Reaction = speed of reactants turning into products

Can be measured in :

or

2626

2727

Effect of the Nature of the Reactant

The nature of the reactants involved will determine the kind of reaction that occurs.

Reactions with bond rearrangements or electron transfer take longer than reactions

without these changes……

2828

Effect of Temperature on Reaction Rate

Increasing the temperature increases

the rate of a reaction. At higher temperatures, the particles have more energy, move faster and collide more

frequently. ….

2929

Effect of Concentration on Reaction Rate

Increasing the concentration of the reactants increases the rate of a

reaction. …..

3030

Effect of Particle Size/Surface Area

Decreasing particle size/increasing surface area increases the rate of a

reaction. When ….

3131

Simulation

3232

Not Cattle List!!

3333

Catalyst - any substance that is added to the reaction to ………

the rate. The catalyst ……….. react with any substance to produce product.

Inhibitor - Any substance added to ………. the rate of reaction.

Works against the catalyst.

3434

C2H2

H2 C2H4

3535

A catalyst increases the rate of a reaction by lowering the activation energy.

3636

Stoichiometry

Batch Systems

Batch Systems (Stoichiometric Table)

Batch Systems (Constant Volume)

Batch Systems (Example)

Exp

ress

ing

conc

entr

atio

n as

a

func

tion

of c

once

ntra

tion

Example 1

Example2

Homework1

Homework2

Homework3