Dehydration of Sugar

 

Summary:  Dry Method

Hazards: 

Use care with concentrated sulfuric acid. 

The fumes given off in this reaction are very irritating.

Chemicals and Solutions: 

85 g granular sugar

60 mL Sulfuric acid, conc.

Materials: 

disposable 7 oz. poly beaker

phototray

100 ml graduated cylinder

glass stirring rod

Procedure: 

Do this demonstration at the end of class so it can be removed immediately.

Measure 85 g sugar into poly beaker.

Add 60 mL concentrated H2SO4 to sugar (After a couple of minutes the sugar turns black and an intense odor of burnt sugar will be noticeable).

 

Discussion: 

The reaction:

C12H22O11 + 11H2SO4 ---> 12C + 11H3O+ + 11HSO4-

C + 2H2SO4 ---> CO2 + 2H2O + 2SO2

Disposal:

Remove the demonstration to a hood and allow it to gas off. Once it has finished gassing off send to EH&S labeled as 95% carbon, 5% sulfuric acid.

 

 

 

Summary:  Wet Method

Hazards: 

Use care with concentrated sulfuric acid. 

The fumes given off in this reaction are very irritating.

Chemicals and Solutions: 

METHOD I - LIQUID

2 M sucrose solution

Sulfuric acid, conc.

METHOD II - DRY

85 g granular sugar

60 mL Sulfuric acid, conc.

Materials: 

METHOD I - LIQUID

1 - disposable 7 oz. poly beaker

1 - phototray

Graduated cylinders, 50 ml and 100 ml

METHOD II - DRY

disposable 7 oz. poly beaker

phototray

100 ml graduated cylinder

glass stirring rod

Procedure: 

METHOD I - LIQUID

Do this demonstration at the end of class so it can be removed immediately.

Measure 50 ml H2SO4 into graduated cylinder.

Measure 60 ml sucrose into 100 ml cylinder.

Combine the sucrose and sulfuric acid carefully in the polybeaker.

METHOD II - DRY

Do this demonstration at the end of class so it can be removed immediately.

Measure 85 g sugar into poly beaker.

Add 60 mL concentrated H2SO4 to sugar (After a couple of minutes the sugar turns black and an intense odor of burnt sugar will be noticeable).

 

Discussion: 

The reaction:

C12H22O11 + 11H2SO4 ---> 12C + 11H3O+ + 11HSO4-

C + 2H2SO4 ---> CO2 + 2H2O + 2SO2

 

To schedule a demonstration, please send an email to the demonstration lab.

 

Contact:

Eric Camp

Lecture Demonstration Technician

Bagley Hall 171

(206) 543-1606

ericcamp@uw.edu

 

Site Map | Contact Us