CM8001

Styrofoam is made of polystyrene and this is readily soluble in acetone. Styrofoam contains a lot of air as it is made with foaming agents, thus when dissolved in acetone, the foam decreases in size as air exits the proton material.
As such, with the evaporation of acetone, the polystyerene hardens and becomes a solid, which is also much denser.

a. Branch LDPE is not very strong and thus has low resistance to being cut.
b. HDPE consists of long linear chains which have a larger extent of intermolecular forces of attraction thus they are stronger. However, due to the branching of LDPE, there is less intermolecular forces of attraction due to the decreased surface area, making it weaker.

No. Paper has lower ductility, so when pulling plastic there will be plastic deformation. This is the breaking of current bonds and forming of new bonds. Some of the initial intermolecular bonds are broken and as molecules slide into their new positions, new intermolecular bonds are formed between adjacent molecules, leading to deformation. However, paper has low ductility, so it does not stretch before breaking, and so it will just tear when pulled.

a. Durable, flexible, non-corrosive, non-toxic.
b. PMMA (polymethyl methacrylate) make up hard contact lenses, while hydroxyethyl methacrylate make up for soft, flexible hydrogel lenses. The desirable properties are non-toxic, hydrophilic, non-reactive, lightweight, transparent, frictionless, non-irritant, permeability to oxygen, neutrally charged, and flexible.
c. The material used for soft contact lenses allow for permeability of oxygen, making it more comfortable and easier to wear. This also makes allows soft contact lenses to be worn for prolonged periods of time, longer than hard contact lenses. Another difference is that soft contact lenses are more flexible and can be put on and taken off with greater ease.