What is the volume (in litres) of oxygen at STP required for complete combustion of 32 g of CH4
(1) 44.8
(2) 89.6
(3) 22.4
(4) 179.2
A mixture of gases contains H2 and O2 gases in the ratio of 1:4 (w/w). What is the molar
ratio of the two gases in the mixture?
1. 1:4
2. 4:1
3. 16:1
4. 2:1
If the Avogadro number NA, is changed from 6.022 x 1023 mol-1 to 6.022 x 1020 mol-1 this would change:
1. The definition of mass in units of grams.
2. The mass of one mole of carbon.
3. The ratio of chemical species to each other in a balanced equation.
4. The ratio of elements to each other in a compound.
20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide
and 8.0 g magnesium oxide. What will be the percentage purity of magnesium carbonate
in the sample? (Atomic weight of Mg = 24)
1. 75
2. 96
3. 60
4. 84
When 50 mL of a 16.9 % (w/v) solution of AgNO3 is mixed with 50 mL of 5.8% (w/v) NaCl solution, then the mass of precipitate formed is:
(Ag = 107.8, N = 14, O = 16, Na= 23,Cl=35.5)
1. | 28 g | 2. | 3.5 g |
3. | 7 g | 4. | 14 g |
The number of water molecules is maximum in -
1. 18 molecules of water
2. 1.8 g of water
3. 18 g of water
4. 18 moles of water
25.3 g of Sodium carbonate Na2CO3 is dissolved in enough water to make 250 mL of solution. If sodium carbonate dissociates completely, molar concentration of sodium ion, Na+ and carbonate ion are respectively (Molar mass of Na2CO3 = 106 g mol-1)
1. 0.955 M and 1.910 M
2. 1.910 M and 0.955 M
3. 1.90 M and 1.910 M
4. 0.477 M and 0.477 M
The number of atoms in 0.1 mole of a triatomic gas is:
(NA=6.02 x1023mol-1)
1. | 6.026 x 1022 | 2. | 1.806x1023 |
3. | 3.600 x 1023 | 4. | 1.800 x 1022 |
10 g of hydrogen and 64 g of oxygen were filled in a steel vessel and exploded. The amount of water produced in this reaction will be:
1. 2 mol
2. 3 mol
3. 4 mol
4. 1 mol
How many moles of lead (II) chloride will be formed from a reaction between 6.5g of PbO and 3.2g of HCl?
(1) 0.044
(2) 0.333
(3) 0.011
(4) 0.029