Advertisements
Advertisements
Question
Solve the following problem:
1.00 g of a hydrated salt contains 0.2014 g of iron, 0.1153 g of sulfur, 0.2301 g of oxygen, and 0.4532 g of water of crystallisation. Find the empirical formula. (At. wt.: Fe = 56; S = 32; O = 16)
Solution
Given: Atomic mass of Fe = 56, S = 32, and O = 16
Mass of iron, sulfur, oxygen, and water = 0.2014 g, 0.1153 g, 0.2301 g, and 0.4532 respectively.
To find: The empirical formula of the compound
Calculation: Since the mass of crystal is 1 g, the % iron, sulfur, oxygen and water = 20.14%, 11.53%, 23.01% and 45.32% respectively.
Moles of Fe = `"% of Fe"/"Atomic mass of Fe"=20.14/ 56` = 0.360 mol
Moles of S = `"% of S"/"Atomic mass of S"=11.53/32` = 0.360 mol
Moles of O = `"% of O"/"Atomic mass of O"=23.01/16` = 1.438 mol
Moles of water = `"% of water"/"Atomic mass of water"=45.32/18` = 2.518 mol
Hence, the ratio of number of moles of Fe : S : O : water is
`0.360/0.360` = 1, `0.360/0.360` = 1, `1.438/0.360` = 4 and `2.518/0.360` = 7
Hence, empirical formula is FeSO4.7H2O.
Empirical formula of the compound = FeSO4.7H2O
APPEARS IN
RELATED QUESTIONS
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.
Explain the term molecular formula.
Solve the following problem:
Work out the percentage composition of constituent elements in the following compound:
Lead phosphate [Pb3(PO4)2]
(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:
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)
Solve the following problem:
The red colour of blood is due to a compound called “haemoglobin”. It contains 0.335% of iron. Four atoms of iron are present in one molecule of haemoglobin. What is its molecular weight? (At. mass: Fe = 55.84)
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:
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 ______.
