Saccarozo: Details of theory + practical exercises and answers

by Johnny Jacks
Sucrose, known by various names including sucrose, table sugar, granulated sugar, white sugar, etc., plays a significant role in the daily nutrition of humans. The forthcoming article will provide a comprehensive explanation of the theory along with practical exercises and answers related to this substance.

Sucrose sugar.

Definition of Sucrose

Sucrose, also known as saccharose, is a disaccharide composed of glucose and fructose molecules with the molecular formula C12H22O11.

It is scientifically referred to as α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside, and its nomenclature ends with “oside” due to its classification as a non-reducing sugar. Sucrose is widely recognized for its significance in the human diet and its natural occurrence in plants, as documented on Wikipedia.

Sucrose is referred to by various names, including:

  • Granulated sugar
  • Table sugar
  • White sugar
  • Brown sugar (containing colored impurities)
  • Cane sugar (derived from cane stalks)
  • Rock sugar (crystalline sugar)
  • Beet sugar (extracted from beets)
  • Jaggery (found in jaggery)
  • Simply sugar

The molecular details of sucrose are as follows:

  • Molecular Formula: C12H22O11
  • Molecular Mass: 342
  • Structural Formula: Sucrose consists of one alpha-glucose and one beta-fructose molecule connected through a 1,2-glycosidic linkage.
The molecular structure of sucrose.

The molecular structure of sucrose.

Due to the linkage between the glucose radical and the fructose moiety, the molecular structure no longer possesses the aldehyde functional group but instead exhibits the characteristics of a multifunctional alcohol.

Natural Occurrence of Sucrose

Sucrose is naturally abundant in plants, including sugarcane, sugar beet, and jaggery. The concentration of sucrose in sugarcane juice can reach up to 13%.

Physical Properties of Sucrose

Sucrose, also known as saccharose, is a type of sugar commonly found in nature, occurring in plants such as sugarcane, sugar beets, and jaggery. Following processing, sucrose can exist in various forms, including fenugreek sugar, table sugar, and rock sugar, among others.

Learn the physical properties of sucrose.

Learn the physical properties of sucrose.

In general, sucrose exhibits the following characteristic physical properties:

  • Sucrose is a crystalline form of sugar. It is colorless, odorless, and possesses a sweet taste. It readily dissolves in water, particularly in hot water.
  • Sucrose has a melting point of 180 degrees Celsius.
  • When heated, molten sucrose decomposes at 186°C, producing caramel (commonly known as caramelized sugar). When subjected to combustion, it yields carbon, carbon dioxide, and water. While water can slowly break down the structure of sucrose through hydrolysis, this process occurs at a very gradual pace. As a result, sucrose can remain in solution for many years with minimal change. However, the addition of the sucrase enzyme accelerates this reaction significantly.
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Chemical Properties of Sucrose

Sucrose lacks the aldehyde functional group, which means it lacks reducing properties commonly found in glucose. Instead, sucrose exhibits the characteristics of a multifunctional alcohol. Conversely, due to its composition comprising two monosaccharide radicals, sucrose is prone to undergo hydrolysis reactions.

Learn the chemical properties of sucrose.

Learn the chemical properties of sucrose.

Hydrolysis Reaction

A crucial reaction involving sucrose is its hydrolysis, typically conducted in an acidic environment. When a sucrose solution is heated with an inorganic acid acting as a catalyst, sucrose undergoes hydrolysis to form glucose and fructose.

Chemical Equation:

C12H22O11 + H2O (under the influence of heat and H+) → C6H12O6 + C6H12O6

Sucrose Glucose Fructose

Sucrose hydrolysis can also take place when enzymes catalyze the reaction.

Reaction with Cu(OH)2

In solution, sucrose reacts with Cu(OH)2 to yield a blue-colored copper-sucrose solution.

Chemical Equation:

C12H22O11 + Cu(OH)2 → (C12H21O11)2Cu + 2H2O

Preparation of Sucrose – The Process of Producing Sucrose from Sugarcane

Currently, sucrose is prepared from sugarcane, sugar beet, or jaggery flowers.

Sugarcane can be transformed into either raw or refined sugar. However, not everyone is familiar with the sucrose production process from sugarcane. You can learn about the sucrose production process from sugarcane through the following stages: Extraction of sugarcane juice (permeation or diffusion) → mixing with raw sugar → cleansing of sugarcane juice → chemical processing → settling process – sintering → filtration process → removal of solutes without precipitation → bleaching → concentration process → sugar crystallization → Centrifugal process → sugar drying → sugar screening and classification.

Applications of Sucrose

Sucrose plays a vital role in human health and daily life, serving specific functions in various fields.

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For humans: Sucrose provides energy equivalent to 3.94 kcal per 1g for the human body. This type of sugar is also rapidly digested and can help regulate food intake, preventing obesity. Additionally, sucrose serves as an energy reserve to be used when the body requires immediate sugar.

In the food industry: Sucrose is a crucial ingredient, functioning as a sweetening additive or a primary component in confectionery and soft drinks, among other products. Furthermore, sucrose is utilized for mirror coating and thermoforming.

In the medical field: Sucrose is used in the production of medicines to treat, control, prevent, and alleviate conditions or syndromes such as burning tongue and cough. It also serves as a raw material for pharmaceuticals.

In science and technology: Sucrose is employed in isomaltulose production technology in conjunction with Enterobacter sp. Isb025 bacteria.

Exercises on sucrose in Chemistry Textbook 9 with detailed explanations

From the detailed theories of sucrose above, you will apply that knowledge to solve some basic exercises in the following 9th chemistry textbook.

Practice doing Chemistry exercises.

Practice doing Chemistry exercises.

Solving Lesson 1, Page 155 of Chemistry Textbook 9:

When preparing a beverage with ice, you have two options:

a) Add ice to water, add sugar, then stir. b) Add sugar to water, stir until dissolved, then add ice.

Suggested Answer:

Option b is the correct method because adding sugar to water first allows for easier dissolution as the water’s temperature remains higher (higher temperatures facilitate better dissolution).

Solving Lesson 2, Page 155 of Chemistry Textbook 9:

Write the chemical equations for the following conversion process: Sucrose → Glucose → Ethyl alcohol.

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Suggested Answer:

Chemical equations:

C12H22O11 + H2O → C6H12O6 + C6H12O6 (2) C6H12O6 → 2C2H5OH + 2CO2

Solving Lesson 3, Page 155 of Chemistry Textbook 9:

Explain why the top of sugar cane often develops the smell of ethyl alcohol when left exposed to the air for an extended period.

Suggested Answer:

When sugar cane is left in the open air for an extended period, the sucrose within the cane undergoes fermentation due to the presence of bacteria and moisture in the air. This fermentation process converts sucrose into glucose and subsequently into ethyl alcohol.

C12H22O11 + H2O → C6H12O6 + C6H12O6 (2) C6H12O6 → 2C2H5OH + 2CO2

Solution to Lesson 4, Page 155 of Chemistry Textbook 9:

Describe the chemical method for distinguishing between three solutions: glucose, ethyl alcohol, and sucrose.

Suggested Answer:

To differentiate between the three solutions, follow these steps:

  • Take separate test samples of each substance and label them accordingly.
  • Allow the test samples to react with Ag2O in NH3 solution. The substance that exhibits a silver coating reaction is glucose, which manifests as a gray substance adhering to the walls of the test tube.

    Reaction: C6H12O6 + Ag2O → C6H12O7 + 2Ag (catalyst: NH3)

  • The remaining substances are ethyl alcohol and sucrose.
  • Add HCl solution to two separate samples and then heat them to initiate a hydrolysis reaction. Take the hydrolysis products and react them with AgNO3/NH3 solution.
  • If a white precipitate forms, it indicates the presence of initially sucrose. This happens because sucrose undergoes hydrolysis to produce glucose, which participates in a silver coating reaction to form the precipitate Ag.
  • If no precipitate forms, it indicates the presence of ethyl alcohol.

    Reaction: Sucrose → Glucose + Fructose (due to heating)

Solving Lesson 5, Chemistry 9 Textbook, Page 155:

From 1 ton of sugarcane juice containing 13% sucrose, how many kilograms of sucrose can be obtained, assuming a sugar recovery efficiency of 80%?

Suggested Answer:

In 1 ton of sugarcane juice containing 13% sucrose, there is 0.13 tons (or 130 kilograms) of sucrose.

With an 80% sugar recovery efficiency, the mass of sucrose obtained is calculated as follows:

130 kg × 80% = 104 kg.

The preceding article has presented comprehensive theory and practical exercises related to sucrose. If you found this information helpful, please consider sharing the article. Visit the website daily for updates on interesting knowledge about various compounds and their applications in learning and practical use.

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