Advertisements
Advertisements
प्रश्न
A gaseous hydrocarbon contains 82.76% of carbon. Given that its vapour density is 29, find its molecular formula.
[C = 12, H = 1]
Advertisements
उत्तर
% of carbon = 82.76%
% of hydrogen = 100 - 82.76 = 17.24%
| Element | % weight | Atomic weight | Relative No. of moles | Simplest Ratio |
| C | 82.76 | 12 | 82.76/12 = 6.89 | 6.89/6.8 = 1 x 2 = 2 |
| H | 17.24 | 1 | 17.24/1 = 17.24 | 17.24/6.89 =2.5 x 2 = 5 |
Empirical formula = C2H5
Empirical formula weight = 2 × 12 + 1 × 5 = 24 + 5 = 29
Vapour density = 29
Relative molecular mass = 29 × 2 = 58
N = `"Relative molecular mass"/"Empirical weight"`
= `58/29` = 2
Molecular formula = n x empirical formula
= 2 x C2H5
= C4H10
APPEARS IN
संबंधित प्रश्न
Empirical formula of a compound is CH2O. If its empirical formula is equal to its vapour density, calculate the molecular formula of the compound.
What weight of sulphuric acid will be required to dissolve 3g of magnesium carbonate?
[Mg = 24, C =12, 0 = 16 ]
MgCO3 + H2SO4 → MgSO4 + H2O+ CO2
Washing soda has the formula Na2CO3.10H2O.What is the mass of anhydrous sodium carbonate left when all the water of crystallization is expelled by heating 57.2 g of washing soda?
Chlorine, nitrogen, ammonia and sulphur dioxide gases are collected under the same conditions of temperature and pressure.
Copy the following table which gives the volumes of the gases collected, and the number of molecules (X) in 20L of nitrogen.You are to complete the table by giving the number of molecules in th e other gases, in terms of X.
| Gas | Volume(litres) | Number of molecules |
| Chlorine | 10 | |
| Nitrogen | 20 | X |
| Ammonia | 20 | |
| Sulphur dioxide | 5 |
Calculate the percentage of platinum in ammonium chloroplatinate (NH4)2PtCl6.
[N = 14, H = 1, Pt = 195, Cl =35.5]
(Give your answer correct to the nearest whole number)
Calculate the volume of oxygen required for the complete combustion of 8.8 g of propane (C3H5).
(Atomic mass: C = 14, O = 16, H = 1, Molar Volume = 22.4 dm3 at STP.)
Calculate the relative molecular mass of:
(NH4)2 Cr2O7
Calculate the number of atoms of each kind in 5.3 grams of sodium carbonate.
Correct the statement, if required.
Under similar conditions of temperature and pressure, two volumes of hydrogen combined with two volumes of oxygen will give two volumes of water vapour.
A gas cylinder can hold 1 kg of hydrogen at room temperature and pressure. What mass of carbon dioxide can it hold under similar conditions of temperature and pressure?
