(a)
Interpretation:
For the given solution the values of
Concept Introduction:
Number average molar mass:
Number average molar mass
Weight average molar mass:
Weight average molar mass
(a)
Answer to Problem 25.50QP
The number average molar mass of the given solution is
The weight average molar mass of the given solution is
Explanation of Solution
Given information,
Five molecules with molar masses
Calculate the number average molar mass
The number average molar mass of the given solution is
Calculate the weight average molar mass
The weight average molar mass of the given solution is
(b)
Interpretation:
The number average molar mass is equal to weight average molar mass when all the molecules have identical molar mass, this has to be explained.
Concept Introduction:
Number average molar mass:
Number average molar mass
Weight average molar mass:
Weight average molar mass
(b)
Explanation of Solution
Given information,
All the five molecules have identical molar masses
Calculate the number average molar mass
The number average molar mass of the given solution is
Calculate the weight average molar mass
The weight average molar mass of the given solution is
(c)
Interpretation:
Explanation for the comparison of weight and number average molar masses gives us information about the distribution of the size of
Concept Introduction:
Number average molar mass:
Number average molar mass
Weight average molar mass:
Weight average molar mass
(c)
Explanation of Solution
Given information,
Polyethylene and poly(vinyl chloride) is given as example.
The number and weight average molar mass values will be closer when a small spread in the distribution of sizes of
On the other hand, the number and weight average molar mass values will have larger difference when a large spread in the distribution of sizes of polymer chains in the sample.
(d)
Interpretation:
Myoglobin and cytochrome c have the same number and weight average molar mass values, but this is not the case for hemoglobin this has to be explained.
Concept Introduction:
Number average molar mass:
Number average molar mass
Weight average molar mass:
Weight average molar mass
(d)
Explanation of Solution
Given information,
Myoglobin and cytochrome c have the same number and weight average molar mass values, but this is not true in the case for haemoglobin.
Myoglobin and cytochrome c have no subunits so there are no dissociations and hence both have equal number and weight average molar mass values
On the other hand, haemoglobin molecule has four subunits and in solution those molecules will dissociate to a varying extent so there is a distribution of molar mass
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Chapter 25 Solutions
Chemistry
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