20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0 g of magnesium oxide.
The percentage purity of magnesium carbonate in the sample will be:
(Atomic weight of Mg=24)
1. | 75 | 2. | 96 |
3. | 60 | 4. | 84 |
A mixture of gases contains H2 and O2 gases in the ratio of 1 : 4 (w/w). The molar ratio of the two gases in the mixture will be:
1. | 1:4 | 2. | 4:1 |
3. | 16:1 | 4. | 2:1 |
25.3 g of sodium carbonate, Na2CO3, is dissolved in enough water to make 250 mL of a solution. If sodium carbonate completely dissociates, the molar concentrations of sodium ion, Na+ and carbonate ion, are respectively:
(molar mass of Na2CO3 = 106g 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 volume occupied by one water molecule (density = 1 g cm-3) is:
1.
2.
3.
4.
The volume of oxygen gas (O2) needed to completely burn 1 L of propane gas (C3H8) (both O2 & propane measured at 0°C and 1 atm) will be:
1. 7 L
2. 6 L
3. 5 L
4. 10 L
An organic compound contains carbon, hydrogen, and oxygen. Its elemental analysis gave C, 38.71%, and H, 9.67%. The empirical formula of the compound would be:
1. | CH3O | 2. | CH2O |
3. | CHO | 4. | CH4O |
The moles of lead (II) chloride that will be formed from a reaction between 6.5 g of PbO and 3.2 g of HCl are:
1. 0.044
2. 0.333
3. 0.011
4. 0.029
Concentrated aqueous sulphuric acid is 98% H2SO4 by mass and has a density of 1.80 g mL-1. The volume of acid required to make one litre of 0.1 M H2SO4 solution is:
1. 11.10 mL
2. 16.65 mL
3. 22.20 mL
4. 5.55 mL
1. | 40 mol | 2. | 10 mol |
3. | 20 mol | 4. | 30 mol |
If 2.74 g of the metal oxide contains 1.53 g of metal, then the empirical formula of vanadium oxide is:
(Atomic Mass of V = 52)
1.
2.
3.
4.