Advertisements
Advertisements
Question
An organic compound, whose vapour density is 45, has the following percentage composition,
H = 2.22%, O = 71.19% and remaining carbon. Calculate its empirical formula.
Solution
As we know, molecular weight is 2 x vapour density.
∴ Molecular weight of compound = 2 x 45 = 90
∵ H2 + O2 = 2.22 + 71.19 = 73.41 < 100
The third element of organic compound C = 100 − 73.41 = 26.59%
| Element | Percentage | Atomic Weight | Ratio | Simplest Ratio |
| C | 26.59 | 12 | `26.59/12` = 2.22 | `2.22/2.22` = 1 |
| H | 2.22 | 1 | `2.22/1` = 2.22 | `2.22/2.22` = 1 |
| O | 71.19 | 16 | `71.19/16` = 4.44 | `4.44/2.22` = 2 |
∴ The empirical formula of the given organic compound = CHO2
APPEARS IN
RELATED QUESTIONS
The equation for the burning of octane is:
\[\ce{2C8H18 + 25O2 -> 16CO2 + 18H2O}\]
What is the empirical formula of octane?
On analysis, a substance was found to contain:
C = 54.54%, H = 9.09%, O = 36.36%
The vapour density of the substance is 44, calculate its empirical formula.
An organic compound contains H = 4.07%, Cl = 71.65% chlorine and remaining carbon. Its molar mass = 98.96. Find its Empirical formula.
A hydrocarbon contains 4.8g of carbon per gram of hydrogen. Calculate:
find the empirical formula.
Determine the formula of the organic compound if its molecule contains 12 atoms of carbon. The percentage compositions of hydrogen and oxygen are 6.48 and 51.42 respectively.
A compound X consists of 4.8% carbon and 95.2% bromine by mass. Determine the empirical formula of this compound working correctly to one decimal place (C = 12; Br = 80).
The following experiment was performed in order to determine the formula of a hydrocarbon. The hydrocarbon X is purified by fractional distillation.
0.145 g of X was heated with dry copper (II) oxide and 224 cm3 of carbon dioxide was collected at S.T.P.
Calculate the empirical formula of X by the following step:
Calculate the number of moles of carbon dioxide gas.
The following experiment was performed in order to determine the formula of a hydrocarbon. The hydrocarbon X is purified by fractional distillation.
0.145 g of X was heated with dry copper (II) oxide and 224 cm3 of carbon dioxide was collected at S.T.P.
Calculate the empirical formula of X by the following step:
Calculate the mass of carbon contained in this quantity of carbon dioxide and thus the mass of carbon in sample X.
The following experiment was performed in order to determine the formula of a hydrocarbon. The hydrocarbon X is purified by fractional distillation.
0.145 g of X was heated with dry copper (II) oxide and 224 cm3 of carbon dioxide was collected at S.T.P.
Calculate the empirical formula of X by the following step:
Calculate the mass of hydrogen in sample X.
The following experiment was performed in order to determine the formula of a hydrocarbon. The hydrocarbon X is purified by fractional distillation.
0.145 g of X was heated with dry copper (II) oxide and 224 cm3 of carbon dioxide was collected at S.T.P.
Calculate the empirical formula of X by the following step:
Deduce the ratio of atoms of each element in X (empirical formula).
