Advertisements
Advertisements
प्रश्न
Explain the term molecular formula.
उत्तर
- Molecular formula of a compound is the formula which indicates the actual number of atoms of the constituent elements in a molecule.
e.g. The molecular formula of benzene is C6H6. - It can be obtained from the experimentally determined values of percent elemental composition and molar mass of that compound.
- Molecular formula can be obtained from the empirical formula if the molar mass is known.
Molecular formula = r × Empirical formula
r = `"Molecular mass"/"Empirical formula mass"`
APPEARS IN
संबंधित प्रश्न
Choose the correct option:
By decomposition of 25 g of CaCO3, the amount of CaO produced will be ________
Two elements A (At. mass 75) and B (At. mass 16) combine to give a compound having 75.8 % of A. The formula of the compound is ______.
Choose the correct option:
The hydrocarbon contains 79.87% carbon and 20.13% of hydrogen. What is its empirical formula?
Choose the correct option:
How many grams of oxygen will be required to react completely with 27 g of Al? (Atomic mass: Al = 27, O = 16)
Choose the correct option:
In CuSO4.5H2O the percentage of water is ______
(Cu = 63.5, S = 32, O = 16, H = 1)
Explain the term percentage composition.
Explain the term empirical formula.
Solve the following problem:
Work out the percentage composition of constituent elements in the following compound:
Potassium dichromate (K2Cr2O7)
(At. mass: Pb = 207; P = 31; O = 16; K = 39; Cr = 52; Na = 23; N = 14)
Solve the following problem:
Work out the percentage composition of constituent elements in the following compound:
Macrocosmic salt - Sodium ammonium hydrogen phosphate, tetrahydrate (NaNH4HPO4.4H2O)
(At. mass: Pb = 207; P = 31; O = 16; K = 39; Cr = 52; Na = 23; N = 14)
Solve the following problem:
Find the percentage composition of constituent green vitriol crystals (FeSO4.7H2O). Also, find out the mass of iron and the water of crystallisation in 4.54 kg of the crystals. (At. mass : Fe = 56; S = 32; O = 16)
A substance, on analysis, gave the following percent composition: Na = 43.4%, C = 11.3% and O = 45.3%. Calculate the empirical formula. (At. mass Na = 23 u, C = 12 u, O = 16 u).
Solve the following problem:
Assuming the atomic weight of a metal M to be 56, find the empirical formula of its oxide containing 70.0% of M.
Solve the following problem:
An organic compound containing oxygen, carbon, hydrogen, and nitrogen contains 20% carbon, 6.7% hydrogen, and 46.67% nitrogen. Its molecular mass was found to be 60. Find the molecular formula of the compound.
Solve the following problem:
A compound on analysis gave the following percentage composition by mass: H = 9.09; O = 36.36; C = 54.55. Mol mass of compound is 88 g mol−1. Find its molecular formula.
Solve the following problem:
Carbohydrates are compounds containing only carbon, hydrogen, and oxygen. When heated in the absence of air, these compounds decompose to form carbon and water. If 310 g of a carbohydrate leaves a residue of 124 g of carbon on heating in absence of air, what is the empirical formula of the carbohydrate?
An organic compound on analysis gave C = 42.8%, H = 7.2% and N = 50%. Volume of 1 g of the compound was found to be 50 mL at STP. Molecular formula of the compound is ______.
