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Selina solutions for Class 8 Chemistry chapter 3 - Elements, Compounds and Mixtures

Selina Concise Chemistry - Middle School for Class 8 (2018-19 Session)

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Selina Selina Concise Chemistry - Middle School Class 8 (2018-19 Session)

Selina Concise Chemistry - Middle School for Class 8 (2018-19 Session) - Shaalaa.com

Chapter 3: Elements, Compounds and Mixtures

Chapter 3: Elements, Compounds and Mixtures solutions [Page 0]

Define:

(a) Elements

(b) Compounds

 

Give two examples for each of the following:
(a) Metals (b) Non-metals
(c) Metalloids (d) Inert gases

Differentiate between:
(a) Pure and impure substances
(b) Homogenous and heterogenous substances

Write the chemical name of the following and also give their molecular formulae:
(a) Baking soda (b) Vinegar
(c) Marble (d) Sand

Name:
(a) a soft metal
(b) a metal which is brittle
(c) a non-metal which is lustrous
(d) a liquid metal
(e) a metal which is a poor conductor of electricity.
(f) a non-metal which is a good conductor of electricity.
(g) a liquid non-metal
(h) the hardest naturally occurring substance
(i) an inert gas

How is sodium chloride different from its constituent elements ?

Why is iron sulphide a compound ?

Chapter 3: Elements, Compounds and Mixtures solutions [Page 0]

Classify the following substances into compounds and mixtures:

Give one example for each of the following types of mixtures
(a) solid-solid homogenous mixture
(b) solid-liquid heterogenous mixture
(c) misicible liquids
(d) liquid-gas homogenous mixture

Tick the most appropriate answer.

How many times is a proton heavier than an electron?

  1. 1500
  2. 1800
  3. 1840
  4. none of these

Suggest a suitable technique to separate the constituents of the following mixtures. Also give the reason for selecting the particular method.
(a) Salt from sea water
(b) Ammonium chloride from sand
(c) Chalk powder from water
(d) Iron from sulphur
(e) Water and alcohol
(f) Sodium chloride and potassium nitrate
(g) Calcium carbonate and sodium chloride

(a) Define mixture.
(b) Why is it necessary to separate the constituents of a mixture.
(c) State four differences between compounds and mixtures.

(a) What is chromatography ? For which type of mixture is it used ?

Choose the most appropriate answer 

a mixture of sand and ammonium chloride can be separated by

  1. filtration
  2. distillation
  3. sublimation
  4. crystallisation

Choose the most appropriate answer

 A pair of metalloids are

  1. Na and Mg
  2. B and Si
  3. C and P
  4. HeandA

Choose the most appropriate answer 

 Which of the following property is not shown by compounds?

  1. They are heterogeneous.
  2. They are homogeneous.
  3. They have definite molecular formulae.
  4. They have fixed melting and boiling points

Choose the most appropriate answer 

 A solvent of Iodine is

  1. Water
  2. Kerosene oil
  3. Alcohol
  4. Petrol

Choose the most appropriate answer

Which of the gas is highly soluble in water ?

  1. Ammonia
  2. Nitrogen
  3. Carbon monoxide
  4. Oxygen

Fill in the blank

A pure substance has definite.................. and constant ..............

Fill in the blank

Mixtures can be ...................... or .....................

Fill in the blank

Use of a ................. to separate the components of a mixture of solids is based on the difference in the size of the components

Fill in the blank

................. is used when the constituents of a mixture of solids have difference in their weights

Fill in the blan

Iodine, camphor, naphthalene, ammonium chloride and dry ice are some substances that ....................................

Chapter 3: Elements, Compounds and Mixtures solutions [Page 0]

Tick the most appropriate answer.

The constituents of a mixture are present in

  1. a fixed ratio
  2. a variable ratio,
  3. the ratio of 2: 1
  4. none of these

Tick the most appropriate answer

Solutions are

  1. heterogeneous mixtures.
  2. compounds
  3. homogeneous mixtures.
  4. elements

Tick the most appropriate answer

The methods of separating components of a given mixture are based on the

  1. physical properties and state of the components.
  2. colour of the components only.
  3. state of the components.
  4. none of these

Tick the most appropriate answer

 Winnowing is the method used to separate

  1. chaff from grain.
  2. stones from rice
  3. oil from water
  4. salt from sand

Tick the most appropriate answer.

 Loading is a process in which

  1. impurities become heavy and sink to the bottom.
  2. impurities float on the top.
  3. impurities vaporize.
  4. none of these

Tick the most appropriate answer.

During filtration the substance left behind on the filter paper is called

  1. distillate
  2. filtrate
  3. sublimate.
  4. residue

Tick the most appropriate answer

 Fractional distillation is used to separate liquids having an appreciable difference in their

  1. size and shape
  2. solubility
  3. boiling points.
  4. none of these

Tick the most appropriate answer.

 The different constituents of an ink are separated by

  1. handpicking.
  2. paper chromatography
  3. filtration.
  4. magnetic separation

Chapter 3: Elements, Compounds and Mixtures solutions [Page 0]

Fill in the blank

A .................. substance has only one kind of matter.

Fill in the blank

The composition and properties of a ......................... mixture is uniform throughout.

 Fill in the blan

An ................ is a homogeneous mixture of two or more metals.

Fill in the blank

Chalk powder dissolved in water is an example of a Chalk powder dissolved in water is an example of a .......................

Fill in the blank

An ...................... is formed when one liquid is dispersed as tiny droplets throughout another liquid

Fill in the blanks.

Immiscible liquids are separated by using a ........................

Chapter 3: Elements, Compounds and Mixtures solutions [Page 0]

Write true or false 

All pure substances have characteristic melting and boiling points.

Write true or false 

Milk is an emulsion.

 Write true or false 

A heterogeneous mixture has a uniform composition throughout the mixture

Write true or false 

The constituents of a mixture can only be separated by chemical means

 Write true or false

Handpicking can be used as a separation technique if the particle size of the constituents of the mixture is the same.

Chapter 3: Elements, Compounds and Mixtures solutions [Page 0]

 Match the columns.

         column A           column B

1. to separate grain from chaff  

a. filtration 
2.  to saparate sawdust from water   b. sedimentation and deeantation 
3. to separate iodine from sodium chloride  c. winnowing 
4. to separate iron fillings from sand  d.sublimation 

5. it is used to separate sand and water 

e maganetic separation 

 

f .handpicking 

 

Chapter 3: Elements, Compounds and Mixtures solutions [Page 0]

Differentiate between the following

Supernatant liquid and Fill rate

 Differentiate between the following.

Filter Paper and Alum

Chapter 3: Elements, Compounds and Mixtures solutions [Page 0]

Is food that we eat a mixture ?

Name two methods by which solid-solid mixtures can be separated.

How can you separate iron metal from non-magnetic impurities ?

Name the technique that you use if only the solid component of a solution is required.

Name the substance you will add to speed up sedimentation.

Name the different types of chromatographic techniques.

Chapter 3: Elements, Compounds and Mixtures solutions [Page 0]

What is the difference between a pure substance and a mixture ?

What are the different types of mixtures ?

Why is filtration a better technique than sedimentation and decantation ?

How is distillation method different from evaporation?

What is centrifugation ? Also write the principle on which it works.

Chapter 3: Elements, Compounds and Mixtures

Selina Selina Concise Chemistry - Middle School Class 8 (2018-19 Session)

Selina Concise Chemistry - Middle School for Class 8 (2018-19 Session) - Shaalaa.com

Selina solutions for Class 8 Chemistry chapter 3 - Elements, Compounds and Mixtures

Selina solutions for Class 8 Chemistry chapter 3 (Elements, Compounds and Mixtures) include all questions with solution and detail explanation. This will clear students doubts about any question and improve application skills while preparing for board exams. The detailed, step-by-step solutions will help you understand the concepts better and clear your confusions, if any. Shaalaa.com has the CISCE Selina Concise Chemistry - Middle School for Class 8 (2018-19 Session) solutions in a manner that help students grasp basic concepts better and faster.

Further, we at Shaalaa.com are providing such solutions so that students can prepare for written exams. Selina textbook solutions can be a core help for self-study and acts as a perfect self-help guidance for students.

Concepts covered in Class 8 Chemistry chapter 3 Elements, Compounds and Mixtures are Concept of Elements, Compounds and Mixture, Separation of the Components of a Mixture, Emphasis on the Principle of Separation.

Using Selina Class 8 solutions Elements, Compounds and Mixtures exercise by students are an easy way to prepare for the exams, as they involve solutions arranged chapter-wise also page wise. The questions involved in Selina Solutions are important questions that can be asked in the final exam. Maximum students of CISCE Class 8 prefer Selina Textbook Solutions to score more in exam.

Get the free view of chapter 3 Elements, Compounds and Mixtures Class 8 extra questions for Chemistry and can use Shaalaa.com to keep it handy for your exam preparation

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