Concept explainers
Calculate the number of molecules present in each of the following samples.
l type="a">
i>4.75 g of phosphine,
i>
i>1.25 X 10 2 moles of lead(II) acetate,
i>a sample of benzene,
- , which contains a total of 5.40 moles of carbon
(a)
Interpretation:
The number of molecules of substance should be calculated.
Concept Introduction:
Number of moles is related to mass and molar mass as follows:
Here, m is mass and M is molar mass.
According to Avogadro’s law, 1 mole of a substance contains
Thus, number of molecules can be calculated from number of moles using the following conversion factor:
Answer to Problem 39QAP
Explanation of Solution
Number of moles of phosphine
First convert mmol into mol as follows:
Thus, number of moles will be:
Since, 1 mole of phosphine contains
Therefore, number of molecules in phosphine is
(b)
Interpretation:
The number of molecules of substance should be calculated.
Concept Introduction:
Number of moles is related to mass and molar mass as follows:
Here, m is mass and M is molar mass.
According to Avogadro’s law, 1 mole of a substance contains
Thus, number of molecules can be calculated from number of moles using the following conversion factor:
Answer to Problem 39QAP
Explanation of Solution
Mass of posphine is 4.75 g.
Calculate number of moles as follows:
Molar mass of phosphine is 34 g/mol, putting the values,
Since, 1 mole of phosphine contains
Therefore, number of molecules in phosphine is
(c)
Interpretation:
The number of molecules of substance should be calculated.
Concept Introduction:
Number of moles is related to mass and molar mass as follows:
Here, m is mass and M is molar mass.
According to Avogadro’s law, 1 mole of a substance contains
Thus, number of molecules can be calculated from number of moles using the following conversion factor:
Answer to Problem 39QAP
Explanation of Solution
Mass of lead (II) acetate is
Calculate number of moles as follows:
Molar mass of lead (II) acetate is 325.3 g/mol, putting the values,
Since, 1 mole of lead (II) acetate contains
Therefore, number of molecules in lead (II) acetate is
(d)
Interpretation:
The number of molecules of substance should be calculated.
Concept Introduction:
Number of moles is related to mass and molar mass as follows:
Here, m is mass and M is molar mass.
According to Avogadro’s law, 1 mole of a substance contains
Thus, number of molecules can be calculated from number of moles using the following conversion factor:
Answer to Problem 39QAP
Explanation of Solution
Number of moles of lead (II) acetate is
Since, 1 mole of lead (II) acetate contains
Therefore, number of molecules in lead (II) acetate is
(e)
Interpretation:
The number of molecules of substance should be calculated.
Concept Introduction:
Number of moles is related to mass and molar mass as follows:
Here, m is mass and M is molar mass.
According to Avogadro’s law, 1 mole of a substance contains
Thus, number of molecules can be calculated from number of moles using the following conversion factor:
Answer to Problem 39QAP
Explanation of Solution
Total number of moles of carbon is 5.40 mol.
From the formula of benzene
Since, 1 mole of benzene contains
Therefore, number of molecules in benzene is
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Chapter 8 Solutions
Introductory Chemistry
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