The volume of oxygen liberated at STP from 15 mL of 20 volume H2O2 is
100 mL
200 mL
300 mL
400 mL
Calculate the molality of a solution that contains 51.2 g of naphthalene (C10H8) in 500 mL of carbon tetrachloride. The density of CCl4 is 1.60 g/mL
0.250 m
0.500 m
0.750 m
0.840 m
When 2.46 gm of a hydrated salt (MSO4xH2O) is completely dehydrated, 1.20 gm of anhydrous salt is obtained. If the molecular weight of anhydrous salt is 120 gm mol-1, what is the value of x?
2
7
4
6
B.
7
Molecular weight of MSO4 = 120 g/mol
Molecular weight of MSO4.xH2O = 120 gm + x × 18 gm
(120 gm + x × 18 gm) of MSO4.xH2O on complete dehydration gives 120 gm of MSO4.
1 gm gives =
Then, 2.46 gm of MSO4.xH2O gives which is equal to 1.20 gm.
295.2 = 1.20 × 120 + 1.20 × 18x
295.3 = 144 + 21.6 x
295.2 - 144 = 21.6 x
x = = 7
x = 7
Therefore, the value of x = 7
An organic compound contains 90% carbon and 10% hydrogen by mass. Its empirical formula is
C2H4
C3H6
C3H8
C3H4
How many molecules of CO2 are formed when one milligram of 100% pure CaCO3 is treated with excess hydrochloric acid?
6.023 × 1023
6.023 × 1018
6.023 × 1021
6.023 × 1022
5.0 g of sodium hydroxide (molar mass 40 g mol-1) is dissolved in little quantity of water and the solution is diluted upto 100 ml. What is the molarity of the resulting solution?
0.1 mol dm-3
1.0 mol dm-3
0.125 mol dm-3
1.25 dm-3
0.02 mole of [Co(NH3)5Br]Cl2 and 0.02 mole of [Co(NH3)5Cl]SO4 are present in 200 cc of a solution X. The number of moles of the precipitates Y and Z that are formed when the solution X is treated with excess barium chloride are respectively.
0.02, 0.02
0.01, 0.02
0.02, 0.04
0.04, 0.02
A 100% pure sample of a divalent metal carbonate weighing 2 g on complete thermal decomposition releases 448 cc of carbon dioxide at STP. The equivalent mass of the metal is
40
20
28
12
Molar heat capacity of aluminium is 25 JK-1 mol-1. The heat necessary to raise the temperature of 54 g of aluminium (atomic mass 27 g mol-1) from 30°C to 50°C is
1.5 kJ
0.5 kJ
1.0 kJ
2.5 kJ