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Atoms and molecules

Write down the names of following formulae:
(i) Al2(SO4)3
(ii) CaCl2
(iii) K2SO4
(iv) KNO3
(v) CaCO3

Atoms and molecules

Write down the formulae of
(i) sodium oxide
(ii) aluminium chloride
(iii) sodium sulphide
(iv) magnesium hydroxide

Atoms and molecules

Why is it not possible to see an
atom with naked eyes?

Atoms and molecules

Define the atomic mass unit.

Atoms and molecules

Which postulate of Dalton’s
atomic theory can explain the law
of definite proportions?

Atoms and molecules

Which postulate of Dalton’s
atomic theory is the result of the
law of conservation of mass?

Atoms and molecules

Hydrogen and oxygen combine in
the ratio of 1:8 by mass to form
water. What mass of oxygen gas
would be required to react
completely with 3 g of hydrogen
gas?

Atoms and molecules

In a reaction, 5.3 g of sodium
carbonate reacted with 6 g of
acetic acid. The products were
2.2 g of carbon dioxide, 0.9 g
water and 8.2 g of sodium acetat. Show that these observations are in agreement
with the law of conservation of
mass.
sodium carbonate + acetic acid
→ sodium acetate + carbon
dioxide + water

Is matter around us pure?

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

Is matter around us pure?

Classify the following into elements, compounds and mixtures.
(a) Sodium
(b) Soil
(c) Sugar solution
(d) Silver
(e) Calcium carbonate
(f) Tin
(g) Silicon
(h) Coal
(i) Air
(j) Soap
(k) Methane
(l) Carbon dioxide
(m) Blood