Select Page

Subject:

science-chemistry

Class:

class VI

Key Concepts

, solids, liquids, gases, metals and non metals, lustre, sonorous, malleable, homogenous mixture, heterogeneous mixture, hand-picking, winnowing, threshing, sieving, sedimentation, decantation, filtration and evaporation

essential questions

1. How do pure substances and mixtures compare?
2.How can matter be classified?
3. How is matter classified?
4. How can mixtures be separated?

Remembering:

  1. Which of the following is a good conductor of heat? a) wood b) glass c) graphite  d) rubber
  2. Butter paper is: a) transparent b) translucent  c) opaque
  3. Copper metal: a) never rusts b) is a good conductor of electricity c) is a poor conductor of heat d) all of these
  4. A substance that allows the heat to pass through it is called:  a)luster    b) conductor   c) opaque  d) insulator
  5. Select the magnetic material  a) Iron vessel    b) polythene     c) balloon   d) aluminum
  6. _______ is a mixture of two or more materials. a) solubility b) solvent c) solution
  7. Which of the following is an important fuel? a) carbon dioxide    b) natural gas    c) helium    d) oxygen
  8.  Iron is separated from the mixture by: a) magnetic separation   b) sedimentation   c) winnowing   d) sieving
  9.  The process of settling down of the particles of an insoluble solid in a liquid is called:  a) decantation   b) sedimentation   c) winnowing   d) sieving
  10. Air is a:  a) pure substance   b) heterogeneous mixture   c) the compound of oxygen and nitrogen   d) homogeneous mixture
  11.  The process of changing vapor into its liquid is called: a) condensation  (b) loading (b) winnowing  (d) evaporation
  12. List three properties of mixtures.
  13. Describe the process called loading.
  14.  (a) State one use of the method of winnowing.(b) Give one use of the ‘handpicking’ method of separating mixtures in daily life.
  15. What is winnowing?
  16. What is the saturated solution?
  17. Name the process by which water is separated from rice and pulses after washing them.
  18. Which method is usually used to separate small pieces of stones from pulses at home?
  19. Define pure substances.
  20. Which substance is used for loading the clay particles suspended in muddy water?
  21. What are the various categories in which classification of materials takes place?
  22. What do you understand between Miscible and Immiscible liquids?
  23. Fill in the Blanks:
    1. Materials which contain two or more substances in any proportion are called——————.
    2. —————— mixtures are not uniform in appearance and composition.
    3. Cereals like wheat and rice are sources of————-.
    4. The process in which a liquid change into vapour is called———————–.
    5. —————— is a process of separating the component of substances from a liquid mixture by selecting evaporation and condensation

understanding:

  1. Nails are made up of metal because it: a) shiny   b) does not bend easily   c) rusts
  2.  Woods is used for matches because it: a) burns b) rots  c) floats
  3. Which of the following is a heterogeneous mixture? a) a salt solution  (b) a salt-pepper mixture (c) air  (d) a fizzy drink
  4. Which of the following is a homogeneous mixture?  a) mist   b) a sand-water mixture  c) an oil-water mixture d) a nitrogen-oxygen mixture
  5.  Tiny pieces of stones are usually separated from pulses before cooking by the method called : a) threshing  b) sieving  c) hand picking  d) winnowing
  6. Which of the following does not represent a characteristic of pure substance? a) It has a uniform texture throughout (homogeneous) b) It has fixed boiling or melting point  c) It is made up of different types of particles  d) It can be an element or a compound
  7. What are the characteristics of metals : a) Good conductors of electricity, and sonorous, solid at room temperature, transparent shine bright when polished  b) Good conductors of electricity and heat; soild at room temperature, opaque except in extremely thin films; donot shine at all when polished   c) bad conductors of electricity and heat; solid at room temperature opaque except in extremely thin films  d)  Good conductors of electricity and heat; solid at room temperature; opaque except in extremely thin films; shine brightly when polished
  8. Select and incorrect reason for separating components of a mixture: a) to separate two or more different but useful components  b) to remove undesirable and useless components  c) to remove pure or harmless components  d) to obtain pure sample of a substance
  9. What happens if a saturated solution of sugar is cooled to a lower temperature?
  10. Do you agree with statement ‘sea water is a heterogeneous mixture’. Give reasons for your answer.
  11. Suppose your mother wants to remove pieces of vegetables from a large quantity of soup. Find out how she can do that quickly?
  12.  There are four mixtures A, B, C and D. The mixture A contains sand and sugar, mixture B contain chalk powder and salt, mixture C contains salt and sugar, whereas mixture D contains sugar and charcoal powder. Which one of these mixtures cannot be separated by using water as a solvent? Why
  13. How will you separate a mixture of common salt, sand and iron filings?
  14.  Explain with the help of a diagram how can a mixture of oil and water be separated?
  15. Define solubility of a substance. How does the solubility of a substance vary with temperature?
  16. What do you mean by immiscible liquids? How are they separated?
  17. Why is sorting or classification of materials important?

Application:

  1. Material C is stretchy but not an absorbent. Material D is a good absorbent but does not stretch. Which will make the best swimwear? a) Material D b) Material C  c) material C and make good swimwear.
  2. A solid substance is dissolved in water. Which of the following methods is used for separating it?
    (a) distillation (b) evaporation (c) filtration  (d) decantation
  3. Oil and water can be separated through  a) filter paper   b) distillation  c) evaporation   d) separating funnel
  4. Why do you often need to separate mixtures into their components?
  5. Three groups of mineral are given below: Group 1: Salt, sugar , flour   Group 2: Copper, Gold, Silver   Group 3: Petrol, Kerosene, paper   Identify the property common to each group:

a)  Group 1- Solid     Group 2- Bad conductors of heat     Group 3- Liquid

b) Group 1- Edible     Group 2- Non Metallic                 Group 3- Inflammable

c) Group 1- Edible     Group 2- Metallic                       Group 3- Inflammable

6. Match the column I with column II and select the correct option from the codes given:

Column I                                                                    Column II

P Chalk- Water                                                     i) A gaseous mix- mix

Q Glucose solution                                           ii) Solid- gas mix

R Fizzy drink                                                    iii) Homogeneous solid- liquid mix

S Smoke                                                            iv)  A heterogeneous solid liquid mix

T Air                                                                   v) A gas- liquid mix

a) P-iii  Q-iv   R-v   S-i  T-ii     b) P-v  Q-iii R-iv S-ii  T- i    c) P-ii  Q-i  R-iv  S-v  T-iii   d) P-iv  Q-iii  R- v  S-ii  T-i

 

Analysis:

  1. Which of the following statement is / are correct: Statement 1: Larger solid particles can be separated from smaller ones by filtration  Statement 2: Cream can be separated from milk by churning  Statement 3: A mixture of mud and water can be separated by loading, sedimentation and decantation  Statement 4: Grains can be separated from stalks by threshing. Choose the correct option:  a) I and II only   b) II and IV only  c) I, II and III    d) II, III and IV only
  2. Take 10 ml of water in 6 test tubes each and add different samples of substances to each test tube. Shake the test tube vigorously for a couple of seconds and them undisturbed for 5 minutes. In which of these test tubes, sample substance will remain insoluble in water.  Test Tube 1= Sugar     Test Tube 2= Salt   Test Tube 3= Sand  Test Tube 4= Chalk Powder   Test Tube 5= Saw dust    Test Tube 6= Washing powder  Choose the correct options:  a) 1,2 and 3    b) 2,3 and 4    c) 3,4 and 5    d) 4, 5 and 6
  3. A few statement about centrifugation method are given below:  Statement 1: The mixture containing very small suspended particles is rotated at a high speed in centrifugal machine  Statement 2: The denser particles stay at the top  Statement 3: The method is used to separate water from wet clothes in a washing machine  Statement 4: The method can be used in lab for separating plasma and platelets. Choose the correct options: a) Statement 1 and 4 only   b) Statement 1, 2 and 3 only   c) Statement 2,3 and 4 only   d) Statement 1,3 and 4 only
  4. Depending on nature of constituents present in a mixture, Seema suggested some methods of separation as shown in the table:

Type of Mix                                                         Method of separation 

  1. Solid- solid                                                          handpicking and sieving

2. Solid- Liquid (insoluble)                                    Sedimentation, decantation, filtration

3. Liquid-Liquid (immisicible)                          Decantation, separating funnel

4. Solid- Liquid (soluble)                                   Filtration, Decantation

5. Liquid- Liquid (Miscible)                            Distillation

Choose the correct the option:  a) Only 1 and 2    b) Only 3    c) Only 1 and 5    d) Only 4

 

Evaluation:

  1. A science teacher labelled 3 glass slide P,Q,R. She painted Q with light blue color, R with black and P was left as such. Then she asked students to put slide on white paper with X mark. Students will be see the mark clearly ( partially)  a) P,Q   b) P,Q,R  c) P, R  d) None of the above
  2. Study the given table showing some daily used items which can be made from more than one material.

 Items                                           Wood                               Plastics                     Metals                      Glass

  1. Cooking pot                              Yes                                    Yes                             X                                 X
  2. Storage container                    Yes                                    Yes                           Yes                               Yes
  3. LPG Cylinder                           Yes                                     Yes                             X                               Yes
  4. Tea Cup                                    Yes                                      Yes                            Yes                             X

Which of the following is incorrect: a) 1 and 4    b) 1,3 and 4    c) 1 and 3    d) 2 and 3

Create: