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SAI INTERNATIONAL SCHOOL
CLASS-VII
SUBJECT- CHEMISTRY
TOPIC-PHYSICAL AND CHEMICAL CHANGES
SUB TOPIC- BROWNING OF FRUITS AND VEGETABLES

PRACTICE WORKSHEET-2

OBJECTIVE/MCQs

1. The chemical formula of rust is
a) Fe2O3.xH2O
b) Fe2O3
c) FeO
d) Fe(OH)2
2. What is depositing a layer of zinc on iron called?
a) Galvanisation
b) Crystallisation
c) Sublimation
d) Layering
3. The reaction where heat is evolved is called a __________reaction
a) Exothermic
b) Endothermic
c) Both a) and b)
d) Precipitation
4. When magnesium is treated with oxygen, the product formed Is_
--------------------
a) Magnesium dioxide
b) Magnesium oxide
c) Magnesium hydroxide
d) Carbon dioxide
5. When milk is converted to curd, an acid is produced. It is________
a) Citric acid
b) Formic acid
c) Lactic acid
d) Acetic acid
6. When carbon dioxide is passed through lime water, a……. colour layer is
formed.
a) Red
b) Yellow
c) Green
d) White

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