Page 155 - Chemistry ICSE Class X
P. 155
Mole Concept and Stoichiometry 141
(v) The ratio between the number of molecules in 2 g of hydrogen and 32 g of oxygen is
(a) 1 : 2
(b) 1 : 0.1
(c) 1 : 1
(d) 0.01 : 1
(vi) The element whose gram-atomic mass and gram-molecular mass are same is
(a) hydrogen
(b) oxygen
(c) nitrogen
(d) helium
(vii) Mass of one Avogadro’s number of oxygen atoms (O) is equal to
(a) 16 u
(b) 16 g
(c) 32 g
(d) 6 kg
(viii) The molecular formula of calcium phosphate is
(a) CaPO
4
(b) Ca (PO )
3
4 2
(c) Ca PO
2
4
(d) Ca(PO )
4 3
(ix) The number of molecules in 8 g of oxygen gas is
23
(a) 6.02 × 10
23
(b) 3.01 × 10
23
(c) 1.5 × 10
12
(d) 3.01 × 10
(x) The correct molecular formula of a compound in which carbon and hydrogen are present in the ratio of
1 : 1.5 is
(a) C H
1.5
1
(b) C H
4
6
(c) C H
3
2
(d) C H
1
1.5
(xi) The percentage of water in Na S.9H O is about
2
2
(a) 75
(b) 68
(c) 45
(d) 90
(xii) A gas cylinder can hold 1 kg of hydrogen at room temperature and pressure. The mass of carbon dioxide it
would hold under similar condition is
(a) 220 kg
(b) 2 kg
(c) 2.2 kg
(d) 22 kg
Answers
(i) (d) (ii) (d) (iii) (d) (iv) (c) (v) (c) (vi) (d) (vii) (b)
(viii) (b) (ix) (c) (x) (c) (xi) (b) (xii) (d)
