STM3305 Chemical Part 3

What type of intermolecular force is responsible for surface tension?

• Dispersion forces

• Dipole-dipole forces

• Ion-dipole forces

• Hydrogen bonds

Which type of intermolecular force is the strongest?

• Dispersion forces

• Dipole-dipole forces

• Ion-dipole forces

• Hydrogen bonds

What is the main factor determining the degree of crystallinity in materials?

• Stereochemistry

• Kinetics of solidification

• Presence of crystallization promoters

• Chemical composition

Which type of material has a definite melting point?

• Glassy

• Ceramic

• Cellulosic

• Crystalline

What is the main purpose of surface treatments on plastic surfaces?

• To enhance surface tension

• To lower surface tension

• To increase interfacial tension

• To decrease interfacial tension

Which type of molecular arrangement leads to a crystalline structure?

• Amorphous

• Random sequence

• Alternately above and below the chain plane

• All methyl groups on the same side of the chain

What is the main factor determining the chemical properties of food packaging materials?

• Atomic and molecular levels

• Type of polyethylene

• Resistance to oxidation

• Density and gas permeability

Which type of intermolecular force is responsible for wetting of a solid surface by a liquid?

• Dispersion forces

• Dipole-dipole forces

• Ion-dipole forces

• Hydrogen bonds

What is the main property of amorphous solids?

• Definite melting point

• Flowing and ductility

• High density

• Regular atomic arrangement

What is the main property of crystalline materials?

• Low gas transmission

• Increased tearing resistance

• Decreased transparency

• Reduced free volume