CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS

CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS

CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS. A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances into another. [1] Classically, chemical reactions encompass changes that only involve the positions of electrons in the formation and breaking of chemical bonds between atoms, without changes in the nuclei (without changes in the elements present), and can often be described by an equation chemistry. Nuclear chemistry is a sub discipline of chemistry that involves chemical reactions of unstable and radioactive elements where both electronic and nuclear changes can occur.CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS.

CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS

CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS
CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS

CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS

CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS. The substance (or substances) initially involved in a chemical reaction are called reagents or reagents. Chemical reactions are generally characterized by a chemical change and give one or more products, which generally have different properties than the reactants. Reactions often consist of a sequence of individual sub steps, so-called elemental reactions, and information about the precise course of action is part of the reaction mechanism. Chemical reactions are described by chemical equations, which symbolically present the starting materials, end products, and sometimes intermediate products, and reaction conditions.CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS.

CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS

CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS
CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS

CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS

CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS. Chemical reactions occur at a characteristic reaction rate at a given chemical concentration and temperature. Generally, reaction rates increase with increasing temperature because more heat energy is available to achieve the activation energy needed to break the bonds between the atoms.

CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS. Reactions can proceed in a forward or backward direction until they are complete or reach equilibrium. Reactions that proceed in the forward direction to approach equilibrium are often described as spontaneous, requiring no input of free energy to advance. Non-spontaneous reactions require the input of free energy to proceed (examples include charging a battery by applying an external electrical energy source or photosynthesis driven by the absorption of electromagnetic radiation in the form of sunlight).CLASS 10th SCIENCE NOTES CHAPTER 2 CHEMICAL REACTIONS AND THEIR PRACTICAL APPLICATIONS.

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UNIT: 2

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Q1. Recognize those characteristics, which indicate that a chemical reaction has taken place.

Ans: The following characteristics indicate that a chemical reaction has taken place.

A change in colour is seen.

Some bubbles may form Solid forms on mixing liquids.

A gas evolves on mixing two substances. A change in temperature may occur.

A liquid is formed by mixing two gases. Smell or taste may change. Volume may change.

Q9. What is fabric dyeing process?

Ans: Different colours and shades are used in the process of fabric dyeing to make them attractive. One way of dyeing is to add dye in hot water and dissolve it completely. Put the fabric in for some time. Dye sticks and forms chemical bonds with the fabric.

Q10. What do you mean by hair dyeing?

Ans: Hair dyeing is a process that changes the colour of a person’s hair. It is available in different forms and shades according to the taste of the consumer. Chemical is applied in hair. It sticks to the hair by making a bond with them.

Q11. What do you mean by photosynthesis?

Ans: Photosynthesis is a chemical process by which green plants prepare their own food. Chlorophyll in the leaves traps energy from sunlight. Water in the plants and carbon dioxide from the atmosphere take reacts in the presence of sunlight and chlorophyll to form glucose and oxygen gas. Plants use glucose as food while oxygen gas releases to the atmosphere.

6CO2+6H2O C6H12O6+6O2

Q12. Describe the process of making pulp and paper?

Ans: Paper making is a two-step process. First pulp is made from a tree bark by adding NaOH and Na2S and heating this material. This changes the bark into fibers. In second step these fibers are bonded together and colours are added. Water is squeezed out and pulp is rolled and dried. These rolls are processed to make papers.

Q14. What do you mean by hazardous waste? What are the harms of hazardous waste?

Ans: Hazardous wastes are the material that pose great threat to human health, animals and the environment. A hazardous waste can be ignitable, corrosive, reactive and toxic.

Q15. What is the significance of a product label?

Ans: A product label is very important for many purposes. It bears valuable information regarding the product. It shows the contents of the product. How are chemicals included and in what percentage. It shows the adverse reactions in certain conditions. It informs about the disposal method of that product.

Q16. How chemical waste disturb human health and the environment?

Ans: Chemical waste is very harmful for human health and environment. It causes lots of diseases like cholera, cough, headache and respiratory disorder. They result in low or high blood pressure. They disturb the beauty of the environment. They pollute land, air and water. They also pose negative effects on marine life.

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Q1. What do you mean by scientific nomenclature?

Ans: Naming of chemical compounds, animals, and plants according to the scientific codes is called scientific nomenclature. In the scientific world, it is extremely important to know the precise information about the object we study and to know what class or type it belongs to. Therefore, the object is given a scientific name, which enables us to understand the object and its components. We use salt in our daily life to make our food tasty. It is usually in white crystal form. Its scientific name is sodium chloride NaCl. It shows that salt comprises of sodium and chlorine molecules.

Q3. Relate chemical reaction of Photosynthesis in everyday life

Ans: We encounter the following chemical reaction in our daily life.

Photosynthesis:

Photosynthesis is a chemical process by which green plants prepare their own food. Chlorophyll in the leaves traps energy from sunlight. Water in the plants and carbon dioxide from the atmosphere take reacts in the presence of sunlight and chlorophyll to form glucose and oxygen gas. Plants use glucose as food while oxygen gas releases to the atmosphere.

6CO2 + 6H2O C6H12O6 +6O

Q4. List methods of chemical disposal and briefly describe each method.

Ans: There are different methods of chemical disposal some of them are the following.

Reducing the use of harmful chemicals:

If we want to minimize the bad effects of harmful chemicals, we have to minimize their use in the industries. The less we use these chemicals, the less they affect us.

Reuse and recycle:

Reuse, recycle or recovery is the process of taking the used items for a next use. It is the process of converting the waste products into new products.

Incineration or Combustion:

Wastes are burned at high temperature to convert them into residue and gaseous products in this typical disposal method.

Landfills:

One of the easiest ways of disposal of wastes is to throw them in a landfill. This method needs proper precautions that can save the environment, natural resources and the people living nearby.

Read the product label and material safety data:

Some chemical products come with disposal instructions right on the label and safety data sheet. Read them and you will find how to dispose it off easily without harming the environment.

Q5. Describe how old tires can be recycled and reused?

Ans. Old tires can be recycled and reused in a number of ways.

  1. Shredding and grinding:

When a tire is shredded, its volume is reduced to one fourth of its original size. This can be used as a raw material in different industries and in the creation of old tires.

  1. Cryogenic Crushing:

In this process tires are freeze at a temperature about -80C. At that temperature the rubber becomes as brittle as glass and can be crushed or broken. The resultant product is usually cleaner.

  1. Pyrolysis:

This process involves destroying tires at a high temperature of 430C. This process turns tires into oil, which can be used as a low cost replacement for diesel fuel.

  1. Retreading:

Retreading is a process through which we can use old tires. A worn casing of a tire that has a good structural quality is taken off and put through a process in which, it gets a new retread and sidewall rubber.

Q6. Explain the impacts and safety consequences of chemical disposal in Pakistan.

Ans. Chemicals in industries, produce many useful products that we use in our daily life. However, these chemicals result in some waste chemical materials that harm the ecosystem of the country. Sometimes these chemicals are released in water that disturb the marine life. One method of disposal is to burn the chemical waste, which is extremely harmful for the atmosphere. It increases greenhouse gases that results in global warming and destruction of ozone layer. These useless chemicals are thrown in the landfills that affect the atmosphere. Chemicals used in agriculture find their way to the food chain and results in various diseases. Chemical waste thrown in the open or residential area destroys the natural beauty of that area.

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