18 Questions
What is the repeating unit in a crystalline solid known as?
Unit cell
In polymer crystals, what are the unit cells made up of?
Molecular segments
How many atoms can be present in a unit cell of a polymer chain depending on its complexity?
Hundreds
Which type of polymers are mainly non-crystalline?
Atactic polymers
What holds the polymer segments together within crystals?
Hydrogen bonding
Which factor plays a crucial role in determining the extent of crystallization and crystal structure in polymers?
Tacticity
What does the ratio of Mw/Mn indicate about a polymer specimen?
The range of molecular sizes
What is the significance of having a Mw/Mn ratio equal to 1.00?
Indicates a monodisperse polymer
What is the Z-average Molar Mass (Mz) primarily quoted for?
Polymers with higher molar mass averages
In copolymerization, what characterizes Alternating Copolymers?
Two different types of repeat units
What distinguishes Block Copolymers from other copolymer types?
Existence of long sequences or blocks of the same type
How would one define a copolymer based on the text provided?
A polymer derived from multiple monomers
What is the definition of the weight fraction Wi?
The mass of molecules of molar mass Mi divided by the total mass of all the molecules present
Why is the weight-average molar mass Mw used rather than Mn for polymeric materials?
Mw is sensitive to the presence of high Mi species
What is the formula for calculating Mn in terms of weight fraction?
(1/ΣWi) * Mi
Which term dominates the behavior in polymeric materials when considering Mw?
High Mi species
In the given blend example, what are the molar masses of C95H192 and C105H212 molecules?
1332 g/mol and 1472 g/mol
If a 2g specimen contains 1g each of C95H192 and C105H212, what are Mn and Mw in this case?
Mn = 1399 g/mol, Mw = 1402 g/mol
Test your knowledge of crystalline solids and unit cells by identifying the repeating patterns of atoms in crystal structures. Explore the differences between molecular and atomic solids in terms of their packing units.
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