Polymers (processing behavior): A material that sets into a permanently infusible shape when heated and pressed is called what? Differentiate between thermoplastic (reversible softening) and crosslinked systems. Choose the correct option.

Difficulty: Easy

Thermoplastic
Thermoset
Chemical compound
Polymer

Correct Answer: Thermoset

Explanation:

Concept/Approach
Thermosets form extensive crosslinks on heating/curing and therefore take a permanent shape; they do not soften upon reheating. Thermoplastics soften repeatedly upon heating (reversible).

Final Answer
Thermoset

← Previous Question Next Question→

More Questions from Chemistry

Fuels (antiknock rating): The octane number scale assigns a value of zero to which reference fuel? Recall the two primary standards used to define octane numbers. Choose the correct option.
Water treatment (permanent hardness): Which method cannot remove permanent hardness due to Ca/Mg chlorides/sulfates? Identify the technique ineffective against non-bicarbonate hardness. Choose the correct option.
Allotropy of phosphorus: What is the molecular formula of elemental (white) phosphorus as commonly encountered? Recall the tetra-atomic molecular form of white phosphorus. Choose the correct option.
Bohr–hydrogen energy levels: If the ionization energy of hydrogen from the ground state equals x kJ mol⁻¹, what energy is required to excite an electron from n = 2 to n = 3? Use Eₙ ∝ −1/n² and compute ΔE between levels. Choose the correct option.
Ore of aluminium (metallurgy): Identify the most important commercial ore of aluminium used for metal extraction. Select the widely occurring hydrated oxide ore. Choose the correct option.
Hydrogen isotopes (nuclear composition): The nucleus of a hydrogen atom (protium) consists of which particles? Consider the most abundant isotope of hydrogen. Choose the correct option.
Radioactivity (safety): Given the half-lives below, which radioactive isotope would be the most dangerous to handle (highest activity per amount)? Assume equal initial amounts; shorter half-life ⇒ greater activity. Choose the correct option.
Atomic ions (electron count): How many electrons are present in the hydrogen ion H⁺? Recall that H⁺ is a proton formed by removing electrons from neutral hydrogen. Choose the correct option.
Genetics (molecular control of heredity): The inherited traits of an organism are primarily controlled by which molecules? Identify the long-term information-storage polymer in cells. Choose the correct option.
Bohr–de Broglie relation: The number of standing de Broglie waves fitting an electron’s circular orbit equals the principal quantum number n. If the maximum magnetic quantum number is +3 (so l = 3), determine the number of waves for the lowest allowed orbit with that l. Choose the correct option.

Discussion & Comments

No comments yet. Be the first to comment!

Join Discussion