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Ch.12 - Solids and Modern Materials
Chapter 12, Problem 83

State whether each of these numbers is a reasonable value for a polymer’s molecular weight: 100 amu, 10,000 amu, 100,000 amu, 1,000,000 amu.

Verified step by step guidance
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Step 1: Understand the concept of molecular weight for polymers. Polymers are large molecules composed of repeating structural units, and their molecular weights can vary widely depending on the number of repeating units.
Step 2: Consider the typical range of molecular weights for polymers. Polymers can have molecular weights ranging from a few thousand to several million atomic mass units (amu).
Step 3: Evaluate the given molecular weights one by one. Start with 100 amu and consider if it falls within the typical range for polymers.
Step 4: Continue evaluating the next molecular weight, 10,000 amu, and determine if it is a reasonable value for a polymer's molecular weight.
Step 5: Repeat the evaluation process for 100,000 amu and 1,000,000 amu, considering whether each value is within the expected range for polymer molecular weights.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Molecular Weight of Polymers

Molecular weight refers to the mass of a molecule, typically expressed in atomic mass units (amu). For polymers, which are large molecules made up of repeating units (monomers), the molecular weight can vary significantly. Commonly, polymers have high molecular weights, often ranging from thousands to millions of amu, depending on their structure and the number of repeating units.
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Polymer Structure and Composition

Polymers are composed of long chains of repeating units called monomers. The properties and molecular weight of a polymer are influenced by the type of monomers used, the degree of polymerization (number of monomer units), and the arrangement of these units. Understanding the relationship between these factors is essential for evaluating whether a given molecular weight is reasonable for a specific polymer.
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Typical Molecular Weight Ranges

Different types of polymers exhibit characteristic molecular weight ranges. For instance, small oligomers may have molecular weights in the hundreds to thousands of amu, while most synthetic and natural polymers, such as polyethylene or proteins, typically have molecular weights in the tens of thousands to millions of amu. Recognizing these ranges helps in assessing the reasonableness of the given molecular weight values.
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