RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance

Rajasthan Board RBSE Class 6 Science Chapter 5 Let Us Know the Substance

RBSE Solutions for Class 6 Science

RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance

RBSE Class 6 Science Let Us Know the Substance Intext Questions and Answers

Page No 37.

Question 1.
Collect things from your nearby places and write their properties in the given table.
Answer:
Table : Things and their properties
RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance-1

RBSE Class 6 Science Let Us Know the Substance Text Book Questions and Answers

Choose the Correct Options:

Question 1.
The gases state has
(a) fixed shape
(b) unfixed shape and volume
(c) fixed volume
(d) fixed mass
Answer:
(c) fixed volume

Question 2.
The main particle of outer part of an atom is –
(a) Proton
(b) Neutron
(c) Proton & neutron
(d) Electron
Answer:
(d) Electron

RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance

Question 3.
The substance made up of only one type of particle is –
(a) compound
(b) element
(c) mixture
(d) mixed metal
Answer:
(b) element

Question 4.
Sugar, salt, glass, plastics are called –
(a) element
(b) compound
(c) mixtures
(d) above all
Answer:
(b) compound

Fill In the blanks:

  1. ………………….. and ………………….. are present in the nucleus of atom.
  2. The particles of solid are ………………….. to each other while particles of gases are …………………..
  3. Sugar is a compound while its syrup is …………………..

Answer:

  1. Proton, neutron
  2. close, far
  3. mixture

Match the following Correctly:

Question 1.
RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance-2
Answer:

  1. (c)
  2. (d)
  3. (b)
  4. (a)

Short Answer Type Questions:

Question 1.
Write names of 5 compounds used in our daily life.
Answer:
Names of 5 compounds used in our daily life are as under –

  • Sugar
  • Lime
  • Salt
  • Detergent.

Question 2.
Draw a labelled diagram of structure of atom.
Answer:
RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance-3

Question 3.
Identity elements, compounds and mixture from the following – oxygen gas, iron, sugar, salt, hydrogen gas, sand, brass, soap, surf, sugar, syrup, sorbet, air.
Answer:
Table of examples of element, compound & mixture
RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance-4
Long Answer Type Questions:

Question 1.
Explain with experiments the state of matter.
Answer:
Take some ice cubes in a bowl. Keep for few minutes. We will observe that ice cubes melts into water. Now heat this water. The water gets converted into steam. From this experiment we can say that Substance have three states of matter solid (ice), liquid (water) and gas (steam).
RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance-5

Question 2.
Define elements, compound and mixtures with examples.
Answer:
1. Element –
Substance made up of a single type of atom is called element. Atoms of elements are similar in their properties.

Example –
Carbon (C), Sulphur (S), Copper (Cu), Silver (Ag) etc.

2. Compound –
When two or more elements combines in fixed ratio through chemical reaction then it is called compound.

Example –
Sugar, Time, Salt, Surf, Soap etc.

3. Mixture –
When two or a more element, compound is mixed in any ratio, they are called mixture.

Example –
Syrup, air, sand etc.

Question 3.
Differentiate atom and molecule with example.
Answer:
The differences between atom and molecules are as follows –
RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance-6

Question 4.
Explain the making of water molecule with diagram.
Answer:
One molecules of water (H2O) is formed from one atom of oxygen (O) and two atoms of hydrogen (H2).
RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance-7

RBSE Class 6 Science Let Us Know the Substance Importent Questions and Answers

Choose the Correct Answer:

Question 1.
On the basis of physic structure, how many states of matter is there –
(a) one
(b) two
(c) three
(d) four
Answer:
(d) four

Question 2.
Those substances whose shape and volume are not fixed are called –
(a) Liquid
(b) Solid
(c) Gas
(d) Plasma
Answer:
(c) Gas

Question 3.
Those substances whose shape and volume are fixed are called –
(a) Liquid
(b) Solid
(c) Gas
(d) Compound
Answer:
(b) Solid

RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance

Question 4.
The positively charged particle of atom are called –
(a) Proton
(b) Neutron
(c) Electron
(d) None of these
Answer:
(a) Proton

Question 5.
What is the formula of water compound?
(a) CO2
(b) HCl
(C) H2O
(d) CO
Answer:
(C) H2O

Fill in the blanks:

  1. Sorbet, air, sand etc. are examples of ………………….. (mixture/compound)
  2. Two or more than two atoms group together to form ………………….. (atom/molecule)
  3. Neutron particle is electrically ………………….. (active/neutral)
  4. The different forms of substances are called its ………………….. (state/structure)
  5. The smallest indivisible part of substance is called ………………….. (molecule/atom)

Answer:

  1. mixture
  2. molecule
  3. neutral
  4. stale
  5. atom

Match Column (1) with Column (2) –

Question 1.
RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance-8
Answer:

  1. (e)
  2. (a)
  3. (b)
  4. (c)
  5. (d)

Very Short Answer Type Questions:

Question 1.
What is matter?
Answer:
Those things that have some mass and occupy some space are called substance or matter.

Question 2.
Give two main properties of sub stances.
Answer:

  • They have mass
  • They occupy space.

Question 3.
What are the basis of classification of substances?
Answer:
Classification of substances has two main basis –

  • Physical structure (composition)
  • Chemical composition.

Question 4.
Name the fourth state of substance.
Answer:
The fourth state of substance is ‘plasma’.

RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance

Question 5.
Name the three states of water.
Answer:

  • Ice (solid)
  • Water (liquid)
  • Steam (Gas).

Question 6.
Classify substances on the basis of their chemical composition.
Answer:
On the basis of chemical composition substances can be classified into three –

  • Element
  • Compound
  • Mixture.

Question 7.
What are the states of matter?
Answer:
The different forms of substances are the states of substances.

Question 8.
What temperature solidification of water starts?
Answer:
The solidification of water starts below 0°C.

Question 9.
At what temperature does water converts into steam?
Answer:
Water converts into steam above 100°C.

Question 10.
Explain mixture with an example.
Answer:
When two or more than two elements or compounds are mixed in any ratio, then it is called mixture.

Example –
Sorbet, sand, air etc.

RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance

Question 11.
Substance is made up of which particles?
Answer:
Substance is made up of very small particles. The smallest particle of substance is atom which is indivisible.

Question 12.
What is the smallest particle of matter called?
Answer:
The smallest particle of matter is called atom. It can not be visible by naked eyes.

Short Answer Type Questions:

Question 1.
Represent the classification of sub stances with the help of a flow chart.
Answer:
RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance-9

Question 2.
What is meant by valency?
Answer:
While forming a compound, atom react with other in a fixed ratio. The combining capacity of any atom is called valency.

Question 3.
Name any five compounds and write their formula.
Answer:
RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance-10

Question 4.
What is plasma? Explain.
Answer:
This state of matter is actually saturated gases slate. This found as hot ionize state. This stale is found in sun, stars, tube lights, T.V. and picture tubes.

Question 5.
What are symbols ¡n chemical science?
Answer:
In chemical science elements are represented by their symbols. We have discovered 118 elements and millions of compounds are formed from them till date. Alphabet or group of alphabets which represents one atom of the substance is called its symbol.

Question 6.
Describe about Maharishi Kanad.
Answer:
In vedic period the great philosopher Kanad authored Veseshik Sutra which is a basic nuclear physics for scientists of West. He propounded the atomic theory in Veseshik philosophy. He gave the concept that atom combines together to build molecules. He ate Tandul particles (also known as Samo rice in Hindi) during meditation and created the philosophy that made his name Kanad’. He was the originator of the particles molecule theory hence called as Kanad. This concept of Maharishi Kanad was approximately 25,000 years old than John Dalton, who told about the nuclear principle.

Essay Type Questions:

Question 1.
Define and describe the properties of solids, liquids and gases.
Answer:
1. Solids –
Those substances that have definite shape and volume are called solid substances. Properties –

  • Solids are very hard.
  • The shape and volume of solids are fixed.
  • The particles in solids are very close to each others.

Example –
Stone, wood, iron etc.

2. Liquids –
Those substances that have definite volume but not definite shape are called liquids. Properties –

  • Indefinite shape but definite volume.
  • Particles arc for from each other in comparison to solids.
  • Take the shape of vessel in which they kept.

Example –
Milk, sorbet, water etc.

3. Gases –
Those substances whose shape and volume are indefinite are called gases. Properties –

  • Gases are colourless.
  • They can flow.
  • Some gases can be felt by smell.
  • The particles of gas are very far from each other.
  • Its shape and volume both are indefinite.

Example –
Oxygen, carbon dioxide etc.

RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance

Question 2.
Explain in detail the structure of atom.
Answer:
Atom has two structural parts –

  1. Nucleic (inner part)
  2. Electronic (outer part)

The inner part of atom is called Nucleus. It has two particles.
1. Proton (p) –
It is positively charged.
RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance-11

2. Neutron (n) –
It is electrically neutral. The outer parts of atom consist of negatively charged particles caJied electron. They circulate around nucleus in definite orbits. Thus atom is made up of main three particies –

  • Proton (p)
  • Electron (e)
  • Neutron (n)

Question 3.
Tabulate the name along with the symbols of some important elements.
Answer:
RBSE Solutions for Class 6 Science Chapter 5 Let Us Know the Substance-12

Question 4.
Write a note on the workings of Indian scientist Satyendra Nath Bose.
Answer:
He was born on 1 January 1894 AD. He was known as father of statistical engineering. Research of Satyendra Nath Bose and scientist Anarico Fermi made possible to differentiated particles of physics into two parts. For this discovery the particles are given their names as Boson and Fermions. National science council awarded Satyendra Nath Bose with Meghnad Saha Smarak gold medal. 1954 he was awarded with Padma Vibhushan.

The principle propounded by Bose is published by famous scientist Einstein. This principle named is Bose Einstein Statistic. With the help of Einstein Satyendra Nath Bose discovered a fifth state of matter as Bose Einstein Condensation which is scientifically proved. That’s why he is known as Indian Einstein.

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