Fill in the blanks :
(a) In______________________change no new substance is formed.
(b) A foul smelling spoiled food is a_______________________change.
(c) Properties such as shape, size, colour and state of a substance are called____________ properties.
(d) Turning of lime water to milky is a standard test of_________________________gas.
(e) A chemical change is also called a_________________________
(f) Photosynthesis is an example of __________________________change.
(g) Burning of any substance is a____________________________change.
(h) Conditions for rusting of iron is ____________________and____________________
(i) The chemical name of vinegar is________________________________
Show with the help of chemical & word equation – the chemical reaction between –
(a) Vinegar and baking soda.
(b) Carbon dioxide and lime water.
(c) Burning of magnesium ribbon.
(d) Magnesium oxide and water.
(e) Rusting of iron & Copper sulfate and iron.
Multiple Choice Questions
Galvanisation is a process used to prevent the rusting of which of the following?
Which of the following statement is incorrect for a chemical reaction?
(a) Heat may be given out but never absorbed.
(b) Sound may be produced.
(c) A colour change may take place.
(d) A gas may be evolved
Which of the following is a physical change?
(a) Rusting of iron
(b) Combustion of magnesium ribbon
(c) Burning of candle
(d) Melting of wax
Which of the following is a chemical change?
(a) Twinkling of stars
(b) Cooking of vegetables
(c) Cutting of fruits
(d) Boiling of water
Short answer type
Differentiate between physical and chemical change with 2 examples of each.
Write down any 4 characteristics of chemical change.
Why is it always advised not to play with fireworks?
What is the role of the Ozone layer in our atmosphere?
(2) Crystallization process.
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Class 7 Maths
Class 7 Science