30 g of magnesium and 30 g of oxygen are reacted, then the residual mixture contains
60 g of magnesium oxide only
40 g of magnesium oxide and 20 g of oxygen
45 g of oxygen and 15 g of magnesium oxide
50 g of magnesium oxide and 10 g of oxygen
Assuming that the density of water to be 1g/cm3, calculate the volume occupied by one molecule of water
2.989 × 10-23 cm3
6.023 × 1023 cm3
22400 mL
18 cm3
Rearrange the following (I to IV) in the order of increasing masses and choose the correct answer (atomic mass: O = 16, Cu = 63, N = 14)
I. 1 molecule of oxygen
II. 1 atom of nitrogen
III. 1 × 10-10 g molecular weight of oxygen
IV. 1 × 10-10 g molecular weight of copper
II < I < III < IV
IV < III < II < I
II < III < I < IV
III < IV < I < II
A metal oxide contains 53% metal and carbon dioxide contains 27% carbon. Assuming the law of reciprocal proportions, the percentage of metal in the metal carbide is
75
25
37
66
5 mL of N HCl, 20 mL of N/2 H2SO4 and 30 mL of N/3 HNO3 are mixed together and volume made to one litre. The normality of resulting solution is:
0.45
0.025
0.9
0.05
What is the percentage of water of crystallisation in a sample of blue vitriol ?
34.07%
35.07%
36.07%
37.07%
10dm3 of N2 gas and 10 dm3 of gas X at the same temperature contain the same number of molecules. The gas X is
CO
CO2
H2
NO
If 1 mL of water contains 20 drops, what is the number of water molecules in the one drop of water ? (A = Avogadro number)
0.5/18 A
0.05 A
0.05/18 A
0.5 A
The number of water molecules present in a drop of water (volume 0.0018 mL) at room temperature is :
6.023 × 1019
1.084 × 1018
4.80 × 1017
6.023 × 1023
The sulphate of a metal M contains 9.87% of M. The sulphate is isomorphous with ZnSO4.7H2O. The atomic weight of M is
40.3
36.3
24.3
11.3
