Advertisements
Advertisements
Question
The Empirical formula of an organic compound is CHCl2.
If its relative molecular mass is 168, what is its molecular formula?
[At. Wt. C = 12, H = 1, Cl = 35.5]
Advertisements
Solution
Empirical formula of organic compound = CHCl2
Molecular Mass (M.M.) = 168
Empirical formula mass
= [12 × 1 + 1 × 1 + 35.5 × 2]
= 12 + 1 + 71
= 84
n = `"Molecular Mass"/"Empirical Formula Mass"`
= `168/84`
Molecular Formula = n × Empirical formula
= 2 × CHCl2
= C2H2Cl4
APPEARS IN
RELATED QUESTIONS
Consider the following reaction and based on the reaction answer the questions that follow:
Calculate:
1) the quantity in moles of (NH4)2Cr2O7 if 63gm of(NH4)2Cr2O7 is heated.
2) the quantity in moles of nitrogen formed.
3) the volume in liters or dm3 of N2 evolved at S.T.P.
4) the mass in grams of Cr2O3 formed at the same time
(Atomic masses: H=1, Cr= 52, N=14]
Ethane burns in oxygen to form CO2 and H2O according to the equation:
`2C_2H_6+7O_2 -> 4CO_2 + 6H_2O`
If 1250 cc of oxygen is burnt with 300 cc of ethane.
Calculate:
1) the volume of `CO_2` formed
2) the volume of unused `O_2`
Give the empirical formula of C6H6.
Give example of compound whose:
Empirical formula is different from the molecular formula.
A compound of lead has following percentage composition, Pb = 90.66%, O = 9.34%. Calculate empirical formula of a compound. [Pb = 207, O = 16]
A compound of X and Y has the empirical formula XY2. Its vapour density is equal to its empirical formula weight. Determine its molecular formula.
Explain the term empirical formula.
In a compound of magnesium (Mg = 24) and nitrogen (N = 14), 18 g of magnesium combines with 7g of nitrogen.
Deduce the simplest formula by answering the following questions:
- How many gram-atoms of magnesium are equal to 18g?
- How many gram-atoms of nitrogen are equal to 7g of nitrogen?
- Calculate the simple ratio of gram-atoms of magnesium to gram-atoms of nitrogen and hence the simplest formula of the compound formed.
A compound is formed by 24 g of X and 64 g of oxygen. If the atomic mass of X = 12 and O = 16, calculate the simplest formula of the compound.
Silicon (Si = 28) forms a compound with chlorine (Cl = 35.5) in which 5.6 g of silicon combines with 21.3 g of chlorine. Calculate the empirical formula of the compound.
