Name ________________________________________________________ Date ____________________ Period _______________
Chemistry of Carbohydrates
Part A. Water
Examine the molecular formula of water, H2O.
1.
2.
3.
4.
What elements make up water? _______________________
What does the number 2 following H tell you? ______________
Why does oxygen not have a subscript? _________________
How many molecules of water are represented by the formula H2O? __________
Examine the structural formula of water.
5. What do the lines between O and H in the structural formula of water represent? _________________
Part B. Carbohydrates
A. Monosaccharides
Glucose
1.
2.
3.
4.
Fructose
Galactose
What does the prefix “mono” mean? _______________________
How many sugars are in one monosaccharide? __________________
What three elements are present in glucose, fructose, and galactose? _____________
Add subscripts to the following that indicate the proper molecular formula. Do this by counting
the total number of carbon, hydrogen, and oxygen atoms in each molecule.
a. Glucose C__H__O__
b. Fructose C__H__O__
c. Galactose C__H__O__
5. How many times larger is the number of hydrogen atoms than oxygen atoms in a molecule of:
Glucose _______
Fructose ________
Galactose _______
6 a. How many times larger is the number of hydrogen atoms than oxygen atoms in a molecule of water,
H2O? ______
b. Is this number the same for monosaccharides? _________
Compare the structural formula of glucose to fructose.
6. a. Are they exactly the same in shape? _____________
b. Are they both monosaccharides? __________
B. Disaccharides
1. What does the prefix “di” mean? _______________________
2. How many sugars are in one disaccharide? __________________
When 2 glucose molecules are chemically joined, a molecule of water has to be removed.
The resulting molecule is called maltose.
3. Write the molecular formula for maltose by adding together the molecular formulas for
glucose and glucose and then subtracting water, H2O. ___________________
Sucrose is another disaccharide. It is formed when a molecule of glucose and a molecule of fructose are
chemically combined.
4. Write the molecular formula for sucrose ______________________________
5. a. How does the molecular formula for sucrose compare to maltose? _____________
b. How many times larger is the number of hydrogen atoms than oxygen atoms in a
disaccharide? ____________
c. How many monosaccharide molecules are needed to form one maltose molecule? ___
d. How many monosaccharide molecules are needed to form one sucrose molecule? ___
e. How do the molecules of maltose and sucrose differ? ______________________
________________________________________________________________
C. Polysaccharides
1. What does the prefix “poly” mean? ____________
The molecular formula for a polysaccharide is written as (C6H10O5)n. The n equals the number of
monosaccharides in the polysaccharide.
2. What is the molecular formula for the polysaccharide starch composed of 33 monosaccharides?
____________________
3. What is the smallest number of glucose molecules that can form a polysaccharide? ___
4 How many times larger is the number of hydrogen atoms than oxygen atoms in a
polysaccharide? ____________
Analysis:
1. Name the 3 categories of carbohydrates covered in this packet. _____________________________________________
_________________________________________________________________________________________________________________________
2. What three elements are present in all carbohydrates? _______________________________________________________
3. Give the names of two monosaccharides studied. _____________________________________________________________
4. Give the names of two disaccharides studied. __________________________________________________________________
5. Give the name of one polysaccharide studied. __________________________________________________________________
6. a. How many times larger is the number of hydrogen atoms than oxygen atoms in ALL carbohydrates?
___________
b. How many times larger is the number of hydrogen atoms than oxygen atoms in water? ____________
7. a. What molecules (do not give specific names) combine to form disaccharides? ___________________________
b. What molecules combine to form polysaccharides? _________________________
8. a. What ends of sugars are removed when sugar molecules join to form either disaccharides or
polysaccharides? ____________________________
b. What molecule do these ends form when they fit together? _________________
9. “Mono-“ means one, “di-“ means two, and “poly-“ means many. Why are these terms used for
describing the three types of sugars? ______________________________________________________________________________
_________________________________________________________________________________________________________________________
10. The word carbohydrate is derived from carbon and water(hydrate). Explain why this combination
correctly describes this chemical group. __________________________________________________________________________
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