Concept explainers
(a)
Interpretation:
Empirical formula for the acid has to be given.
Concept Introduction:
Empirical formula is the one that can be determined from the molar mass of the elements that is present in the compound and the mass percentage of the elements. The mass percentage of the elements present in the compound is converted into the moles of each element considering the molar mass of each element. The relative number of moles for each type of atoms is found out finally.
(a)
Answer to Problem L.38E
Empirical formula for the acid is
Explanation of Solution
Given sample of acid is said to contain
Therefore, the mass of oxygen present in
Number of moles of each element present in the compound can be calculated using the molar mass and mass of the element as follows;
Dividing the moles of element obtained using the smallest amount, the ratio can be obtained as shown below;
The ratio of the atoms in the compound is given as follows;
Thus in compound the atoms are present in the ratio of
Therefore, the empirical formula for the compound can be given as
(b)
Interpretation:
Molecular formula of the unknown acid has to be found out.
Concept Introduction:
Empirical formula is the one that can be determined from the molar mass of the elements that is present in the compound and the mass percentage of the elements. The mass percentage of the elements present in the compound is converted into the moles of each element considering the molar mass of each element. The relative number of moles for each type of atoms is found out finally.
Molecular formula of a compound can be found if the empirical formula and molar mass of the compound is known. The molar mass of compound is divided by the molar mass of the empirical formula in order to obtain the factor which is multiplied with the coefficients of empirical formula in order to obtain the molecular formula.
(b)
Answer to Problem L.38E
Molecular formula of the unknown acid is
Explanation of Solution
Empirical formula of the acid is
From the above equation, it is found that one mole of unknown acid reacts with two moles of sodium hydroxide.
Volume of sodium hydroxide is given as
From the stoichiometric relation, the moles of
Mass of the unknown acid taken is given as
Molar mass of the empirical formula of unknown acid is calculated as follows;
Molar mass of the unknown acid is divided by the molar mass of empirical formula in order to obtain the factor as shown below;
The coefficient of empirical formula is multiplied by the factor
Therefore, the molecular formula of unknown acid is
(c)
Interpretation:
Balanced chemical equation has to be written for the neutralization of the unknown acid with sodium hydroxide.
Concept Introduction:
Chemical equation is a short form representation of a
(c)
Answer to Problem L.38E
Balanced chemical equation is
Explanation of Solution
The unknown acid is said to be diprotic. Consider the unknown acid as
The unknown acid has a molecular formula of
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Chapter F Solutions
CHEMICAL PRINCIPLES 2017 PKG
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