Module 01 Study on the Effect of Pressure Mixing and Temperature Between Baking Soda and Acetic Acid

Module 1 BKF2741 Chemical Reaction Engineering Laboratory I

1.0 Title of Experiment

Study on the effect of pressure, mixing and temperature between baking soda and acetic

acid

2.0 Objective

The objectives of this experiment are to identify the effect factors which affect the rate of

reactions

3.0 Introduction

If any of the products or reactants involved in a chemical reaction is gases, the rate of

reaction will decrease as pressure on the system is increased. The rate of reaction can be

increased if the movement of the reactants is increased as a result of mechanical mixing

(stirring). Nevertheless, it is inversely proportional with mechanical stirring, temperature

and reactant particle size.

A double displacement reaction has the form

AB + CD AC + BD

where A, B, C, and D are atoms or ions. The reaction between acetic acid and baking

soda can be written as a double displacement reaction if carbonic acid (H2CO3) is

considered a product:

HC2H3O2(aq) + NaHCO3(aq) NaC2H3O2(aq) + H2CO3(aq)

Here A, B, C, and D are H+, C2H3O2-, Na+, and HCO3

-, respectively. However, carbonic

acid readily decomposes into carbon dioxide and water,

H2CO3(aq) CO2(aq) + H2O( )

and the carbon dioxide can escape from the solution as a gas. ________________________________________________________________________ FKKSA/BKF2741/Module/Rev01/2/08/10

Module 1 BKF2741 Chemical Reaction Engineering Laboratory I The combined equation is

HC2H3O2(aq) + NaHCO3(aq) NaC2H3O2(aq) + H2O( ) + CO2(g)

At the end of this experiment, student should be able to identify the effect factor of rate of

reaction.

________________________________________________________________________ FKKSA/BKF2741/Module/Rev01/2/08/10

Module 1 BKF2741 Chemical Reaction Engineering Laboratory I 4.0 Experimental Procedure

4.1 The effect of pressure to the rate of reaction

Part A. Rate of Reaction at Normal Pressure

1. Fill up 10ml of vinegar, HCH3O2 in the test tube. The vinegar should be at about

room temperature. Measure the vinegar temperature.

2. Weight 2g of baking soda NaHCO3 and drop the NaHCO3 into the test tube.

3. Measure the time required for the reaction between the baking soda NaHCO3 and

vinegar to be completed and measure the temperature. Record the time.

4. Repeat this experiment twice to get the average values.

Part B. Rate of Reaction Under Increased Pressure

(MAKE AURE YOU PUT ON YOUR SAFETY GOGGLES!)

1. Fill up 10ml of vinegar, HCH3O2 in the test tube. The vinegar should be at about

room temperature.

2. Weight 2g of baking soda NaHCO3 and drop the NaHCO3 into the test tube.

3. Immediately insert the cork stopper in the end of the test tube to slow down the

escape of carbon dioxide gas. The pressure being exerted upon the reactants

inside the test tube is equal to the pressure you feel being exerted against the cork.

Note: Do not try to stop all of the gas from escaping! If you try to do so, the test

tube will break. Just slow down the escaping gas as pressure builds up inside of

the test tube. That pressure acts upon the surface of the liquid. The liquid moves

in a direction that will relieve the pressure. The only direction, without breaking

the test tube, is upward and out. Avoid a total "blow-out" of the liquid from the

tube by releasing enough pressure on the cork from time to time to let gas and

liquid "squeeze" its way past the cork, in controlled amounts. This is a struggle;

you against the gas pressure.



4. When gas bubbles are no longer visible in the liquid contained in the test tube,

consider the reaction to be over. Observe and record the time of the reaction.

5. Release the pressure on the cork.

Note that the reaction starts again. Increase pressure on the cork and the reaction

stops.

Note that if there is still a small amount of baking soda left in the bottom of the

test tube. You have now reached the point when you are able to exert enough

pressure to be equal to the pressure being exerted by the gas inside the test tube.

As a result, the reaction stops. When you release your pressure, the reaction is

able to start again.

6. Remove the cork. Observe and record what happens to the remaining baking soda.

7. Repeat this experiment twice to get the average values


Module 1 BKF2741 Chemical Reaction Engineering Laboratory I 4.2 Effect of mechanical mixing

Part A. Reaction With Stirring

1. Add 100 ml of water to 400 ml beaker. The water temperature should be at or

near room temperature.

2. Add 40 ml of vinegar solution to the beaker. Mix the vinegar and water.

3. Measure out 2g of baking soda.

4. Set the 400 ml beaker on a dark surface so as to provide good contrast with the

white NaHCO3. Add the measured 1/2 teaspoon of baking soda to vinegar

solution and stir continuously.

5. Measure the time required for all of the baking soda to be "used up" in the

reaction with vinegar. Record the time.

Part B. Reaction Without Stirring

1. Add 100 ml of water to 400 ml beaker.

2. Add 40 ml of vinegar solution.

3. Set the beaker on a dark surface so as to provide good contrast with the white

NaHCO3.

4. Add 2g of baking soda; no stirring!

5. Measure the time required for all of the banking soda to react. Record the time.

Part C. Effect of Stirring on Rate of Reaction Where Reactants are Already in

Solution

1. Add 200 ml of water to a 400 ml beaker.

2. Add 20 ml of vinegar solution to the 400 ml beaker.

3. Add 50 ml of water to a 100 ml beaker. Dissolve as much baking soda in the

water as possible.

4. Pour the saturated baking soda solution into the 400 ml beaker containing the

vinegar. DO NOT STIR THE MIXTURE.

5. Measure the time that elapses before the vigorous bubbling action stops.


Module 1 BKF2741 Chemical Reaction Engineering Laboratory I 6. After two minutes, stir the solution. Observe and record the effect that the stirring

has on the reaction.

4.3 Effect of temperature

1. Fill up 20ml of vinegar in a conical flask and heat up at certain temperature as

shown in Table 4.3. For colder temperature of vinegar, you may use ice or

refrigerator to cool the vinegar.

2. Weight 2 g of baking soda and drop it into vinegar. Measure the time required for

tablet to fully dissolve. Be prepared to start and stop on time.

For Clean-Up

All solutions can be safely washed down the drain.


Module 1 BKF2741 Chemical Reaction Engineering Laboratory I 5.0 DATA COLLECTION

Table 5.1

Trial

Time of reaction

Without pressure Pressurized

1

2

3

Average

Observation:_____________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

Table 5.2

Trial Time of reaction

With Stirring Without Stirring Stirring of saturated reactant

1

2

3

Average

Observation:_____________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________



Table 5.3

Initial Vinegar temperature, °C Time of reaction

60

40

30

20

10

Observation:_____________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

Table 5.4

Trial Time of reaction

Tablet Broken pieces Powder

1

2

3

Average

Observation:_____________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________



6.0 Discussion

1. In your point of view, which factor does affect the most rate of reaction?

Elaborate and justify your answer.

2. Does stirring have any effect on the Rate of Reaction if the reacting substances

are already in solution?

3. If you are an engineer, what would you recommend to the investor or client to

enhance the rate of reaction in Continuous Stirred Tank Reactor (CSTR)


Documents

Module 01 Study on the Effect of Pressure Mixing and Temperature Between Baking Soda and Acetic Acid