The trisaccharide formed from the reaction of three glucose (C₆H₁₂O₆) molecules has the formula:
A - VCE - SSCE Chemistry - Question 1 - 2005 - Paper 1
Question 1
The trisaccharide formed from the reaction of three glucose (C₆H₁₂O₆) molecules has the formula:
A. C₁₈H₃₈O₁₈
B. C₁₈H₃₄O₁₇
C. C₁₈H₃₆O₁₆
D. C₁₈H₃₈O₁₅
Worked Solution & Example Answer:The trisaccharide formed from the reaction of three glucose (C₆H₁₂O₆) molecules has the formula:
A - VCE - SSCE Chemistry - Question 1 - 2005 - Paper 1
Step 1
Identify the reaction
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Answer
In a condensation reaction to form a trisaccharide (a carbohydrate composed of three monosaccharides), water molecules are produced as the glucose molecules combine.
Step 2
Calculate the molecular formula
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Answer
The molecular formula for one glucose molecule is C₆H₁₂O₆. For three glucose molecules: 3(C₆H₁₂O₆) gives C₁₈H₆₄O₁₈. However, during the formation of the trisaccharide, 2 water molecules (H₂O) are eliminated:
C18H64O18−2H2O=C18H36O16
Step 3
Select the correct formula
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Answer
Thus, the molecular formula of the formed trisaccharide is C₁₈H₃₆O₁₆, which corresponds to option C.
