Which postulate of Dalton’s
atomic theory can explain the law
of definite proportions?
Which postulate of Dalton’s
atomic theory is the result of the
law of conservation of mass?
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?
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
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
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
Which of the following will show “Tyndall effect”?
(a) Salt solution
(b) Milk
(c) Copper sulphate solution
(d) Starch solution
Identify the solutions among the following mixtures.
(a) Soil
(b) Sea water
(c) Air
(d) Coal
(e) Soda water
Which of the following materials fall in the category of a
“pure substance”?
(a) Ice
(b) Milk
(c) Iron
(d) Hydrochloric acid
(e) Calcium oxide
(f) Mercury
(g) Brick
(h) Wood
(i) Air