a) Define homopolymer and co polymer. [2] b) Differentiate between paper and pulp. [2] c) Distinguish between OPC and PPC cement. [2] d) Write down any two uses of radioisotopes in madical field. [2]

a) Definitions of Homopolymer and Copolymer

• Homopolymer: A homopolymer is a polymer composed of a single type of repeating monomer unit. The entire polymer chain consists of identical structural units. Examples include:
  • Polyethylene (formed from ethylene monomers).
  • Polystyrene (formed from styrene monomers).
  • Polyvinyl chloride (PVC, formed from vinyl chloride monomers).

Ethene (Monomer for Polyethylene)Ethene (Monomer for Polyethylene)Styrene (Monomer for Polystyrene)Styrene (Monomer for Polystyrene)Vinyl chloride (Monomer for PVC)Vinyl chloride (Monomer for PVC)

• Copolymer: A copolymer is a polymer formed from two or more different types of monomer units. The polymer chain contains more than one type of repeating unit, leading to varied properties. Examples include:
  • Styrene-butadiene rubber (SBR, formed from styrene and butadiene).
  • Acrylonitrile butadiene styrene (ABS, formed from acrylonitrile, butadiene, and styrene).
  • Nylon-6,6 (formed from hexamethylenediamine and adipic acid).

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b) Differentiation Between Paper and Pulp

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c) Distinction Between OPC and PPC Cement

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d) Two Uses of Radioisotopes in the Medical Field

1. Diagnostic Imaging (Radiography):

   • Radioisotopes like Technetium-99m (⁹⁹ᵐTc) are widely used in nuclear medicine for diagnostic imaging. They are incorporated into radiopharmaceuticals that emit gamma rays, which are detected by imaging devices (e.g., PET or SPECT scanners) to create detailed images of internal organs. For example:
     • Bone scans: Technetium-99m is used to detect bone abnormalities, infections, or metastases.
     • Cardiac imaging: Radioisotopes help assess blood flow and heart function.

2. Cancer Treatment (Radiotherapy):

   • Radioisotopes such as Cobalt-60 (⁶⁰Co) and Iodine-131 (¹³¹I) are used in radiation therapy to treat cancer. These isotopes emit high-energy radiation that targets and destroys cancerous cells while minimizing damage to surrounding healthy tissue.
     • Brachytherapy: Radioactive seeds (e.g., Iodine-125) are implanted directly into tumors for localized treatment.
     • Thyroid cancer treatment: Iodine-131 is used to ablate thyroid tissue in patients with thyroid cancer or hyperthyroidism.