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Concept explainers
Calculate the number of molecules present in each of the following samples.
oles of sulfur dioxide,
of sulfur dioxide,
:math>
:math>
g of ethane,
![Check Mark](/static/check-mark.png)
(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 40QAP
Explanation of Solution
Number of moles of sulfur dioxide,
Since, 1 mole of sulfur dioxxide contains
Therefore, number of molecules in sulfur dioxide is
![Check Mark](/static/check-mark.png)
(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 40QAP
Explanation of Solution
Mass of sulfur dioxide is 3.54 g.
Calculate number of moles as follows:
Molar mass of sulfur dioxide is 64.066 g/mol, putting the values,
Since, 1 mole of sulfur dioxide contains
Therefore, number of molecules in sulfur dioxide is
![Check Mark](/static/check-mark.png)
(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 40QAP
Explanation of Solution
Mass of ammonia is
Calculate number of moles as follows:
Molar mass of ammonia is 17.031 g/mol, putting the values,
Since, 1 mole of ammonia contains
Therefore, number of molecules in ammonia is
![Check Mark](/static/check-mark.png)
(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 40QAP
Explanation of Solution
Number of moles of ammonia is
Since, 1 mole of ammonia contains
Therefore, number of molecules in ammonia is
![Check Mark](/static/check-mark.png)
(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 40QAP
Explanation of Solution
Mass of ethane is 1.96 mg.
Convert mass from mg to g as follows:
Molar mass of ethane is 30.07 g/mol. Calculate number of moles of ethane as follows:
Putting the values,
Since, 1 mole of ethane contains
Therefore, number of molecules in ethane is
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Chapter 8 Solutions
Introductory Chemistry: A Foundation
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- Calculate, to two decimal places, the formula mass of each of the following substances. Obtain the needed atomic masses from the inside front cover of the text. a. C20H30O (vitamin A) b. C14H9Cl5 (DDT, formerly used as an insecticide) c. C8H10N4O2 (caffeine, a central nervous system stimulant) d. Ca(NO3)2 (calcium nitrate, gives fireworks their red color)arrow_forwardA substance X2Z has the composition (by mass) of 40.0% X and 60.0% Z. What is the composition (by mass) of the compound XZ2?arrow_forwardExpress the composition of each of the following compounds as the mass percents of its elements. a. formaldehyde, CH2O b. glucose, C6H12O6 c. acetic acid, HC2H3O2arrow_forward
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