CBSE Class 7 Science Sample Paper Set 6

CBSE Class 7 Science Sample Paper

SECTION A

1) Fill in the blanks:
A. If soil is acidic, ______ should be added to the soil .
B. Spinach contains ______ acid.
C. Current flows from ________ to ______.
D. An electric heater works on the principle of _______ effect of electric current.
E. The formula of sodium hydrogen carbonate is _______.
F. Making tea is a _______ change.
G. Juices secreted by liver are _______ and ________ .
H. The lining of the small intestine contains finger like projection called_______.

2) Give the terminology for the following:
A. A change in which a substance undergoes a change in its physical properties.
B. The process of depositing a layer of zinc on iron.
C. The substances taste sour because they contain:
D. The solutions which do not change the colour of either red or blue litmus.
E. The process of removal of undigested food through the anus from time to time.
F. The false feet for movement and capture of food in amoeba.

3) Match the following:

A student observed the image and claimed that the frog takes its food by sucking. Is the claim made by the student correct?
(a) No; the frog is eating food as a whole, so its mode of feeding is swallowing.
(b) No; the frog is using teeth to break its food, so its mode of feeding is chewing.
(c) Yes; the frog is pulling in the insect as is done for liquids, so its mode of feeding is sucking.
(d) Yes; the frog is using its body to grind up the insect, so its mode of feeding is sucking 

B. The image shows an experiment set up in which boiled rice was taken in test tube A and boiled, and chewed rice was taken in test tube B:

When the iodine solution is dropped into both the test tubes, the colour of water in test tube A changed to blue black, but the colour in test tube B remained unchanged.
Which of the statements describes the correct reason for this observation?
(a) Chewing adds saliva in the food, which converts the starch into sugars.
(b) Chewing adds starch in the food, which converts the amino acids into proteins.
(c) Chewing adds saliva in the food, which converts the sugar into starch.
(d) Chewing adds starch in the food, which converts the proteins into amino acids

C. When a bit of baking soda is added to vinegar in a test-tube, a hissing sound is heard and several bubbles occur. The test tube is closed and attached by a glass tube to another test tube containing lime water. The limewater slowly turns milky in the process. This is shown in the following experimental setup

Which of the following cannot be considered indicators of a chemical reaction in this experiment?
(a) Occurrence of a hissing sound
(b) The formation of several bubbles
(c) The change in colour of liquid in tube 2
(d) The movement of gas between the test tubes

D. When a candle is lit, what kinds of changes occur in the wax and the wick?

(a) Chemical change in the wick, physical change in the wax
(b) Physical change in the wick; chemical change in the wax
(c) Chemical change in both the wick and wax; physical change in some wax
(d) Physical change in both the wick and the wax; chemical change in the wick

E. A student performs an experiment where he uses a heating coil to heat the water as shown in the image. The initial temperature of the water is measured as 10°C.After switching it on for 5 min, the student records the temperature of the water as 18°C.

The water is allowed to return back to its initial temperature. The activity is then repeated with another heating coil having half the length of the original heating coil. He notices that after 5 min the temperature of the water reads 14°C. Which statement can be concluded based on the activity?
(a) Reading on thermometer reduces with time
(b) Temperature of water drops with every repetition
(c) Length of the material affects the amount of heating
(d) Temperature of the water increases after a certain period of time

F. A student performed an experiment where he placed a magnetic compass near a current carrying wire. He notices some deflection in the compass needle.

What causes the deflection of the needle in the compass?
(a) Magnetic effect of the electric current
(b) Electric effect of the magnetic compass
(c) Magnetic effect of the compass on paper
(d) Electric effect of the paper on the compass

SECTION B

5) Answer the following in short:
A. Amrita made an electric circuit using a cell holder, a switch and a bulb.
When she put the switch in the ‘ON’ position, the bulb did not glow. Help Amrita in identifying the possible defects in the circuit. (2points)
B. (i) How does colour of litmus change for sugar solution?
(ii) What is the colour of Phenolphthalein in acidic solution?
C. Name the source from which litmus solution is obtained. What is the use of this solution?
D. Describe crystallization.
              OR
Describe galvanization
E. Explain why rusting of iron objects is faster in coastal areas than in deserts
F. What is assimilation?
              OR
What is absorption?
G. What is diarrhoea? Why do we use oral Rehydration solution?

6) Answer the following in detail

A. Explain why:
(a) Colour of solution changes when zinc granules are added to copper sulphate solution
(b) During ant sting, one should rub the area with metal.

B. Three liquids are given to you. One is hydrochloric acid; another is sodium hydroxide and third is a sugar solution. How will you identify them? You have only turmeric indicator.
C. Write the reaction for the following:
(a) When magnesium is burnt in air.
(b) Copper sulphate with iron
(c) Vinegar reacts with baking soda

D. What all changes occur in a chemical change? (3 points)
                                  OR
What are different method of prevention of rusting. (3points)
E. Explain the digestion of food in the stomach.
                                  OR
Explain the digestion of food in the small intestine.

F. Write the names and function of gland associated with the digestive tract.

SECTION C

7) Case Based Question
Electric bell consists of a coil of wire. An electromagnet is wound on an iron piece. The coil acts as an electromagnet. An iron strip with a hammer at one end is kept close to the electromagnet. There is a contact screw near the iron strip.
When the iron strip is in contact with the screw, the current flows through the coil which becomes an electromagnet. It, then, pulls the iron strip. In the process, the hammer at the end of the strip strikes the gong of the bell to produce a sound.
However, when the electromagnet pulls the iron strip, it also breaks the circuit.

(i) Name the effect on which electric bell works?
(ii) What is an electromagnet?
(iii) Write 2 uses of electromagnet.
(iv) What are other effects of current?

8) Source Based Question
On the basis of the diagram, answer the following questions:
In the test tubes ‘A’, ‘B’, ‘C’, 3 solution of different substances were kept. Then a few drops of China rose indicator is added to every test tube.
The colours obtained in these test-tube were magenta, colourless and green respectively.

(i) What is kept in test tube A?
(ii) Write the nature of the solution, kept in C.
(iii) Write the nature of the solution, kept in B.
(iv) Name one natural indicator and one synthetic indicator.
(v) Name 2 substances which are acidic in nature.
                                             OR
On the basis of the following picture answer the questions given below:
In an experiment about 10ml of sodium hydroxide solution was taken in a beaker ‘A’. To it was added a few drops of red litmus solution which turned blue. This solution was then taken in beaker ‘B’ and vinegar was added to it drop by drop with continuous stirring. It was observed that the colour of solution in beaker ‘B’ has changed to red.

(i) What is litmus?
(ii) How does vinegar behave in the blue litmus?
(iii) What change in colour is observed when vinegar is added to red litmus?
(iv) How does red litmus change when liquid baking soda is added to it?
(v) What happens when sodium hydroxide reacts with hydrochloric acid?

SECTION D

9) Multiple choice questions

A. When a switch is in OFF position,
(i) circuit starting from the positive terminal of the cell stops at the switch.
(ii) circuit is open.
(iii) no current flows through it.
(iv) current flows after some time.

Choose the combination of correct answers from the following.
(a) all are correct
(b) (ii) and (iii) are correct
(c) only (iv) is correct
(d) only (i) and (ii) are correct

B.

Three bulbs A, B, C are connected in a circuit as shown in Figure. When the switch is ‘ON’
(a) bulb C will glow first.
(b) bulb B and C will glow simultaneously and bulb A will glow after some time.
(c) all the bulbs A, B and C will glow at the same time.
(d) the bulbs will glow in the order A, B and C.

C. A farmer was unhappy because of his low crop yield. He discussed an agricultural scientist realized that soil of his field was either too acidic or two basics. What remedy would you suggest?
(i) It can be treated with quicklime base
(ii) It can be treated with slaked lime.
(iii) It can be treated with organic matter.
(iv) It can be treated with lemon juice.
(a) Statement (i) and (ii) are correct.
(b) Statement (i), (ii) and (iii) are correct.
(c) Statement (i), (ii) and (iv) are correct.
(d) Statement (ii) and (iii) are correct.

D. Raj appeared in the class test where he wrote some statements about acids, but he got confused to know the correct statement. Would you help him know that?
(i) Acids are sour in taste.
(ii) Acids are corrosive in nature.
(iii) Acids are good conductors of electricity.
(iv) Tamarind contains base
(a) Statement (i) and (ii) are correct.
(b) Statement (ii), (iii) and (iv) are correct.
(c) Statement (i), (ii) and (iii) are correct.
(d) Statement (i) and (iv) are correct.

E. STEP 1--Two drops of dilute sulphuric acid were added to 1 gram of copper sulphate powder and then a small amount of hot water was added to dissolve it.
STEP 2-- On cooling, beautiful blue coloured crystal got separated
STEP 1 AND STEP 2 are:
(a) Physical and chemical changes respectively.
(b) Chemical and physical change respectively.
(c) Both physical change
(d) Both chemical change

F. Next two questions are assertion and reason:
Assertion and Reason:
Both A and R are true are true and R is the correct explanation of A.
Both A and R are true but R is not the correct explanation of A.
A is true But R is false.
A is false but R is true.
ASSERTION: Process of taking in food from the environment is called Ingestion.
REASON: Process by which undigested food is ejected out of the body is called assimilation.

G. ASSERTTION: Absorption of water occurs in the large intestine.
REASON: Liver is the largest gland present in the human body.
H. Ankit is writing some sentences. Choose the incorrect one and help him:
(i) Rusting of iron, Photosynthesis and digestion of food are examples of chemical change.
(ii) In order to protect iron from rusting a coating of zinc is deposited on its surface.
(iii) Formation of manure from leaves is a physical change
(iv) Copper sulphate reacts with iron is a physical change
(a) Statement (i), (ii) and (iv) are true
(b) Statement (i) and (ii) are true
(c) Statement (ii), (iii) and (iv) are true
(d) Statement (i),(ii) and (iii) are true

I. A student performs an experiment where a wire is wrapped around a nail as shown in the image. As she completes the circuit, she notices that a nearby nail gets attracted to the nail wrapped in the wire.

What causes the nails to attract each other?
(a) Metal objects always attract each other
(b) Gravitational force causes them to attract
(c) Difference in the size of the nails causes the attraction
(d) Magnetic effect due to the flow of electricity causes the attraction

J. A student requires a magnet for his science project. He decides to prepare a magnet of his own. Which of these arrangements would produce a magnet?