chapter :-2 class :-9 science COMPETENCY BASED (PISA BASED QUESTIONS)

CLASS IX, X , XI , XII , NEET and JEE class 10  

                    COMPETENCY BASED 

                  (PISA BASED QUESTIONS)

                              part :- i

                            chapter :-12
                              class 9

1. . A student is given a mixture of iron filings and sulphur in thee ratio 1 : 2 by weight. He was then asked to heat the mixture over a flame and to observe the olor change. The student will observe that the mixture becomes: .
 

(i) Black
b. Grey
(iii) Yellow
(iv) Orange

... Answer is i)
black"

2. Which of the following is an example of a heterogeneous substance?:. 

(i) distall water
(ii) Table salt.
(iii) Pieces of copper.
(iv) milk

... Answer is iv)
(iv) milk".

 3. White gold is used in jewelry and contains two elements, gold and palladium. A jeweler has two different samples that are both identical in appearance and have a uniform composition throughout. What can be said about the samples? . 
:

(i) They are homogeneous mixtures and be classified as metallic alloys..
(ii)The materials are heterogeneous mixtures and can be classified by their components
(iii) The samples have variable compositions and are classified as metallic solutions.
(iv) The samples are heterogeneous mixtures that can be separated using magnetic properties. .

... Answer is i)
. They are homogeneous mixtures and be classified as metallic alloys..".

4. Compounds:. :

(i) Are the same as mixtures?
(ii) Can be separated by their physical properties.
(iii) Contain only type of element
(iv) Are different kinds of atoms chemically combined with each other?

... Answer is iv)
Are different kinds of atoms chemically combined with each other? ".

5.Which of the following is considered to be a pure substance? .
 

(i) Granite.
(ii) Sodium chloride
(iii) Muddy water
(iv) Milk of magnesia

... Answer is ii)
Sodium chloride".

6. A sample contains two substances and has uniform properties. The sample is:: .
 .

(i) A compound
(ii) A heterogeneous mixture
(iii) An element
(iv)A homogeeous mixture.
... Answer is iv)
A homogeeous mixture ".



7. Which one of the following will result in the formation of a mixture? .
 

(i) Crushing of a marble tile into small particles
(ii) Breaking of ice cubes into small pieces
(iii) Adding sodium metal to water
(iv) Adding milk in water

... Answer is iv)
Adding milk in water".



8. .In which of the following the constituents are present in any ratio?. 


(i) Mixture.
(ii) compound
(iii) element
((iv) Colloid

... Answer is i)
mixture.".



9. Air is regarded as a mixture because: .
 

(i) Its pressure may very
(ii) Its temperature may change
(iii) Its volume changes under different conditions
(iv) Its composition may vary.

... Answer is iv)
(iv)Its composition may vary.".



10. Which of the following is a compound? .
 

(i) Stainless steel
(ii)Bronze.
(iii) Graphite.
(iv) Hydrogen sulphide .

... Answer is iv)
Hydrogen sulphide".