Problem 69 - Chemistry The Central Science

Question

(a) What is the empirical formula of cellulose? (b) What is the monomer that forms the basis of the cellulose polymer? (c) What bond connects the monomer units in cellulose: amide, acid, ether, ester, or alcohol?

Step-by-Step Solution

Answer

(a) The empirical formula of cellulose is \(C_{12}H_{22}O_{11}\). (b) The monomer that forms the basis of the cellulose polymer is glucose. (c) The bond that connects the monomer units in cellulose is an ether bond (specifically, a β(1→4) glycosidic linkage).

Step 1: Determine the empirical formula of cellulose

Cellulose is a polymer made up of repeating glucose units. The empirical formula of glucose is \(C_6H_{12}O_6\). For cellulose, however, we must consider the empirical composition of glucose but lose one molecule of water in the process that occurs when two glucose units are combined (dehydration synthesis). The empirical formula of cellulose can be calculated by subtracting 1 molecule of water from 2 molecules of glucose: 2 x (Glucose) - (Water) = Cellulose 2 x (C_6H_{12}O_6) - H_2O = Cellulose \(C_{12}H_{24}O_{12} - H_2O = C_{12}H_{22}O_{11}\) Thus, the empirical formula of cellulose is \(C_{12}H_{22}O_{11}\).

Step 2: Identify the monomer that forms the basis of the cellulose polymer

Cellulose is a carbohydrate polymer that consists of a repeated single unit, or monomer. In this case, the monomer is glucose, which is a simple sugar or monosaccharide. The glucose units are chemically linked by a specific type of bond, which is addressed in the next step.

Step 3: Determine the bond connecting the monomer units in cellulose

Cellulose is formed when two glucose molecules react and lose a water molecule, creating a new bond between the glucose units. The type of bond formed between the glucose units is known as an ether bond, specifically a β(1→4) glycosidic linkage, which is an oxygen atom that connects two carbon atoms, one from each glucose molecule. By following these steps, we can conclude that: (a) The empirical formula of cellulose is \(C_{12}H_{22}O_{11}\). (b) The monomer that forms the basis of the cellulose polymer is glucose. (c) The bond that connects the monomer units in cellulose is an ether bond (specifically, a β(1→4) glycosidic linkage).