Concept explainers
Analysis of a compound gave 39.50% C, 2.21% H, and 58.30% Cl. When 0.855 g of this solid was dissolved in 7.50 g of naphthalene, the solution had a freezing point of 78.0°C. The pure solvent freezes at 80.0°C; its molal freezing point constant is 6.8°C/m.
- a What is the molecular formula of the compound?
- b What is its molecular weight to the nearest 0.1 g?
(a)
Interpretation:
A compound contains
Concept Introduction:
Depression in freezing point is the phenomenon of lowering of freezing point of a substance, which is considered as solvent, by adding a non-volatile solute. It is expresses as –
Where,
Number of moles of a substance is related to molar mass of the substance as,
Answer to Problem 12.108QP
Molecular formula of the compound is determined as
Explanation of Solution
Given that freezing point of the solution is
Number of moles of the compound considering
Molar mass of the compound is calculated as,
Number of moles of elements in
From the above calculation we could deduce that mole ratio of the elements Carbon, Hydrogen and Chlorine is
(b)
Interpretation:
A compound contains
Concept Introduction:
Depression in freezing point is the phenomenon of lowering of freezing point of a substance, which is considered as solvent, by adding a non-volatile solute. It is expresses as –
Where,
Number of moles of a substance is related to molar mass of the substance as,
Answer to Problem 12.108QP
Molar mass of the compound nearest to tenth of a gram is calculated to be
Explanation of Solution
Molar mass of the compound nearest to tenth of a gram is calculated as,
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Chapter 12 Solutions
General Chemistry - Standalone book (MindTap Course List)
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