# NCERT Solutions for Class 8 Science Chapter 6 Combustion and Flame

NCERT solutions for class 8 science chapter 6 combustion and flame- In the NCERT class 8 science book, chapter 6 is combustion and flame. A thorough study of chapter exercise and solutions of NCERT for class 8 science chapter 6 combustion and flame will be beneficial for class 8 students as concept-based questions are asked from this chapter in exams. Before studying the chapter, you must know that in your day to day life, you use various types of fuels. Be it the LPG fuel used in kitchen or petrol, diesel, CNG in-vehicle, be it wood which is burnt during winters for warmth or cow dung cakes that are used for cooking in villages. The NCERT Solutions for Class 8 Science Chapter 6 combustion and flame are prepared by our subject experts so that students use these solutions to learn the concepts in minimal time. All these fuels work on the same phenomenon which is burning. NCERT Science Class 8 Chapter 6 combustion and flame deals with the chemical process of burning or combustion. It also deals with the details of burning without a flame. After studying the chapter thoroughly, you will be able to attempt the exercise of NCERT textbook and get the correct CBSE NCERT solutions for class 8 science chapter 6 combustion and flame. For middle school students, a tool like NCERT solutions helps extremely in their studies to score decent marks in their examination.

## What is combustion?

Combustion is a chemical process that involves the reaction of a substance with oxygen in order to give away heat. The substance that undergoes combustion is known as fuel. Fuels can be

1. Solid

2. Liquid

3. Gas

In NCERT Science Class 8 Chapter 6 you will majorly learn about these fuels and the process of combustion. On the basis of combustion, materials can be divided into two types

1. Combustible materials

2. Non- combustible materials

While studying  NCERT science Chapter 6 you will also get to know what are combustible and non-combustible materials.

## What is the ignition temperature?

Have ever these questions crossed your mind

1. Why LPG burns so fast while CNG takes some time?

2. Why kerosene is required to burn wood?

The answers to these above-stated questions lie in their ignition temperatures.  It refers to the minimum temperature at which a substance catches fire. Now you can try attempting the above questions. As you will gradually go about the NCERT chapter 6 combustion and flame you will get familiar with the ignition temperature of various substances and how it is important for combustion.

## Inflammable substances

Have you ever seen the sign given below on certain cans or cylinders? This sign refers that there is a highly inflammable substance in the cylinder and you must stay away from it. Inflammable substances are those substances which catch fire very easily.

So, what do you think can we say the ignition temperatures of inflammable substances are very low?  In NCERT solutions for Class 8 Science Chapter 6 Combustion and flame we will talk about the different types of inflammable substances and what are the ways in which we can control fires caused by their burning?

This chapter also deals with flame and its structure. At the end of chapter 6 combustion and flame, you will get to learn about different types of fuels and their efficiency in causing combustion.

## NCERT solutions for class 8 science chapter 6 combustion and flame- Topics

Different topics and subtopics makeup Ch 6 Combustion and flame of NCERT Science Class 8. You can take a look at these topics here as

6.1 What is combustion

6.2 How do we control fire

6.3 Types of combustion

6.4 Flame

6.5 Structure of a flame

6.6 What is fuel

6.7 Fuel efficiency

## NCERT solutions for class 8 science chapter 6 combustion and flame- Preparation tips.

In order to prepare this chapter firstly read the NCERT class 8 science ch 6 combustion and flame. Once you are done with the chapter reading, prepare NCERT science class 8 chapter 6 combustion and flame notes and revise them properly. After proper revision, go for NCERT science class 8 ch 6 combustion and flame worksheets. For better preparation, attempt as many NCERT quizzes for science class 8 chapter 6 as possible. As far as NCERT preparation is concerned, a great understanding of NCERT solutions for science class 8 chapter 6 combustion and flame can be useful for you.

NCERT Solutions For Science Class 8 Chapter 6 Combustion and Flame

Exercise Solutions

The conditions required for the combustion to take place are:

(a) Presence of oxygen

(b) Presence of inflammable substance (fuel)

(c) Maintain Ignition Temperature (the minimum temperature at which substance catches fire).

(a) Burning of wood and coal causes pollution of air.
(b) A liquid fuel, used in homes is LPG(Liquified Petroleum Gas) .
(c) Fuel must be heated to its ignition temperature before it starts burning.
(d) Fire produced by oil cannot be controlled by water .

Fuels like petroleum and coal release toxic gases like carbon monoxide, carbon dioxide, and sulphur dioxide during combustion. These harmful gases cause pollution and respiratory problems.

Whereas CNG (Compressed Natural gas) is a clean fuel and produces these harmful gases in very small quantity.

(CNG is methane stored at high pressure!)

 LPG Wood It does not produce smoke. It produces smoke. It is easy to store and can be easily transported using pipelines. It takes a lot of space to store. It has low ignition temperature It has a high ignition temperature It does not cause environmental pollution It leaves un-burnt carbon particles causing air pollution Calorific value is higher. Calorific value is lower.

Q 5(a). Give reasons.

Water is not used to control fires involving electrical equipment because water being a good conductor of electricity may lead the electric current to spread causing electric shocks or short-circuits

Q 5(b). Give reasons.

Wood produces lots of smoke and unburnt carbon particles, which cause respiratory problems. But LPG does not produce these. Thats why LPG is a better domestic fuel than wood.

Q 5(c) . Give reasons.

Paper by itself catches fire easily whereas a piece of paper wrapped around an aluminium pipe does not.

Paper has a low ignition temperature and hence catches fire easily. But when it is wrapped around an aluminium pipe, heat is transferred to the metal and hence the ignition temperature of the paper is not reached. That is why paper by itself catches fire easily whereas a piece of paper wrapped around an aluminium pipe does not.

Following is the labelled diagram of a candle flame:

The calorific value of a fuel is expressed in kilojoules per kilogram (kJ/kg).

$CO_{2}$  is heavier than $O_{2}$. Therefore, it acts as a blanket over the substance and cuts off the oxygen supply required for combustion. This way $CO_{2}$ is able to control fires.

It is difficult to burn a heap of green leaves but dry leaves catch fire easily because green leaves have moisture present in them. Hence the heat gets absorbed by water to provide energy to evaporate. But, the dry leaves have no moisture and hence the heat is not lost. That is why it catches fire easily.

### Answer: The goldsmith uses the outermost non-luminous (blue) zone for melting gold and silver. This is because it is the hottest part of the flame and hence melts the metals easily.

The calorific value of the fuel is the amount of heat produced by the complete combustion of 1 kg of fuel.

Given, Heat produced by 4.5 kg of fuel  = 180000 kJ

$\therefore$ Heat produced by 1 kg of fuel = 180,000 kJ/4.5 Kg = 40,000 kJ

$\therefore$  The calorific value of the fuel is 40,000 kJ/kg.

The outermost part of the flame is the hottest region of the flame. Hence, water kept near it will get heated faster i.e in shorter time.
Therefore, the water in Ramesh's beaker will get heated in a shorter time.

## NCERT solutions for class 8 science: chapter-Wise

 NCERT solutions for class 8 science chapter 1 Crop Production And Management Solutions of NCERT class 8 science chapter 2 Microorganisms: Friend And Foe CBSE NCERT solutions for class 8 science chapter 3 Synthetic Fibres And Plastics NCERT solutions for class 8 science chapter 4 Materials: Metals And Non-Metals CBSE NCERT solutions for class 8 science chapter 5 Coal and Petroleum NCERT solutions for class 8 chapter 6 Combustion and Flame Solutions of NCERT class 8 science chapter 7 Conservation of Plants and Animals CBSE NCERT solutions for class 8 science chapter 8 Cell Structure and Functions NCERT solutions for class 8 science chapter 9 Reproduction in Animals Solutions of NCERT class 8 science chapter 10 Reaching the Age of Adolescence NCERT solutions for class 8 science chapter 11 Force and Pressure CBSE NCERT solutions for class 8 science chapter 12 Friction Solutions of NCERT class 8 science chapter 13 Sound NCERT solutions for class 8 science chapter 14 Chemical Effects of Electric Current Solutions of NCERT class 8 science chapter 15 Some Natural Phenomena CBSE NCERT solutions for class 8 science chapter 16 Light Solutions of NCERT class 8 science chapter 17 Stars and The Solar System NCERT solutions for class 8 science chapter 18 Pollution of Air and Water

## NCERT Solutions For Class 8: Subject-Wise

 NCERT Solutions for Class 8 Maths NCERT Solutions for Class 8 Science

Benefits of NCERT solutions for class 8 science chapter 6 combustion and flame:

• Homework, as well as revision, becomes an easy task with the CBSE NCERT solutions for class 8 science chapter 6 combustion and flame in hand.
• Similar type questions in the NCERT exercise are expected in the class exams. This is where the NCERT solutions for class 8 science chapter 6 combustion and flame is important.
• You can score well in the exam with the help of these solutions of NCERT for class 8 science chapter 6 combustion and flame.