Which of the following are chemical changes?
(a)Growth of a plant
(b)Rusting of iron
(c) Mixing of iron filings and sand
(d)Cooking of food
(e) Digestion of food
(f) Freezing of water
(g)Burning of a candle.
1 Answers
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What changes in the colour of iron nails and copper sulphate solution do you observe after keeping the iron nails dipped in copper sulphate solution?
Iron nails become reddish brown in colour and solution becomes green in colour.
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Which of the following methods is suitable for preventing an iron frying pan from rusting?
(c) Applying a coating of zinc (We can also apply grease and paint to prevent iron from rusting. However, in case of iron frying pan, grease and paint cannot be applied...
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Define growth, differentiation, development, dedifferentiation, redifferentiation, determinate growth, meristem and growth rate.
(a) Growth It is an irreversible and permanent process, accomplished by an increase in the size of an organ or organ parts or even of an individual cell. (b) Differentiation It is a...
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List three measures used to prevent rusting of iron
Galvanization (coating iron by a more reactive metal) Greasing/oiling Painting.
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Classify the following as chemical or physical changes: • cutting of trees, • melting of butter in a pan, • rusting of almirah,
Cutting of trees → Physical change Melting of butter in a pan → Physical change Rusting of almirah → Chemical change Boiling of water to form steam → Physical...
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Rusting of an article made up of iron is called (a) corrosion and it is a physical as well as chemical change
(c) corrosion and it is a chemical change
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Which of the following are physical changes? (i) Melting of iron metal (ii) Rusting of iron
(c) (i), (iii) and (iv)
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Classify the changes involved in the following processes as physical or chemical changes:
Physical Changes: (b) Dissolving sugar in water, (d) Melting of wax, (e) Beating Aluminium to make Aluminium foil. Chemical Changes: (a) Photosynthesis, (c) Burning of coal, (f) Digestion of food
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When a candle burns, both physical and chemical changes take place. Identify these changes.
Physical Changes: On heating, candle wax gets melted is a physical change. Since it again turns into solid wax on cooling. Chemical Changes: The wax near to flame burns and gives...
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Name a plant hormone that promotes growth. How do these hormones bring about phototropism in the shoot of a plant ?
Auxins promote growth of plants. When light falls on one side of the plant, auxins diffuse towards shady side of the shoot. This concentration of auxin stimulates the cells to grow...
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