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Q.5 Match the column- 5x1=5
(i) Liver (a) Lactic acid
(ii) Lohi (b) Physical Change
(iii)Metals (c) bile juice
(iv) Curd (d) Good quality wool
(v) Wax (e) good conductors
(f) Acetic acid
Q.6 Give two example for each- 5x1=5
(i) Chemical change-
(ii) Natural Indicator
(iii) Conductors-
(iv) Animal fibers
(v) Ruminants-
Q.7 Give Reason for the following 4x2=8
(i) Cows are called ruminants.
(ii) Shearing is done in summer or spring season.
(iii) Cooking utensils are made of aluminum.
(iv) Toothpastes prevent tooth decay.
Or
Stainless Steel does not get rusted.
Q.8 Short Answer type questions? 6x3=18
(i) Why do ships get damaged in spite of being painted?
(ii) Why does a doctor give an antacid to treat indigestion?
(iii) Why is mercury used in thermometer?
(iv) What are the three grades of silk?
(v) Explain physical change & chemical change with two example for each.
(vi) Distinguish between Natural fibers & synthetic fibers.
Answers
Answer:
Q5..
1) liver = c) bile juice
2) lohi = d) good quality wool
3) metals = e) good conductors
4) curd = a) lactic acid
5) wax = b) physical change
Q6..
(i) Chemical change-
a) milk going sour
b) Digestion of food
(ii) Natural Indicator-
a) china rose
b) turmeric
(iii) Conductors-
a) human body
b) water
(iv) Animal fibers-
a) wool
b) silk
(v) Ruminants-
a) cow
b) sheep
Q7..
(i) because the largest pouch of the stomach is called the rumen.
(ii) because sheep can survive without their protective coat of hair.
(iii) aluminium has a very high affinity for oxygen. So, it reacts with oxygen and forms a layer of aluminium oxide on its surface.
(iv) because of the interaction between its alloying elements and the environment.
Q8. .
(i) The salt water makes the process of rust formation faster. Therefore, ships suffer a lot of damage from rusting in spite of being painted.
(ii) Antacids help to treat heartburn (indigestion). They work by neutralizing the stomach acid that causes heartburn.
(iii) mercury has high coefficient of expansion. Hence, the slightest change in temperature is notable when it's used in a thermometer.
(iv) There are three main grades of silk, categorized as A, B, and C. Grade.
(v) A physical change is a type of change in which the form of matter is altered but one substance is not transformed into another. example pink colour of water
A chemical change occurs when a new substance is formed through a chemical reaction.
example ripen of fruits
(vi) Natural fibers or natural fibres are fibers that are produced by plants, animals, and geological processes. for example wool and silk
Synthetic fabrics and textiles made from man-made rather than natural fibres. for example rayon and nylon