a. C6(H20)6
b.
c. Different sweeties. Different chemical structures of each isomer of fructose bond to different sensory receptors on the tongue, leading to slightly different taste of each isomer.

Everything is made of chemical compounds. The concept of chemical-free is therefore impossible. chemical compound is defined as the molecular structure, all are made up of molecules

Acetone dissolves the polymer, which allows the gas of the foaming agent to escape, causing the polymer the collapse on itself and become more dense.

a. LDPE cannot be used in this application because it does not have the required strength.
b. To have the strength in this application, the HDPE molecules must line up in a way that produces the required strength, which the linear molecules allows the sufficient flexibility.

When plastic is stretched, the molecules become aligned parallel to each other and in the direction of the pull. This change in its structure is irreversible and if the pulling continues the plastic will break. When paper is pulled, the paper tears instead of stretching. The cellulose molecules in paper are held rigidly in place, thus they are not free to become aligned as in plastic.

a. The four properties are:
(1) stable over time of intended use
(2) non-toxic.
(3) Lack of solubility in body fluids
(4) Lack of reactivity in body fluids
b. Several types of polymers are commonly used. Polymethyl methacrylate (PMMA), fluoro-silicone-acrylate polymers and fluoro-silicones. Polymacon (38% water) is typical of the polymers used for soft lenses and is a polymer of 2-hydroxyethyl methacrylate (HEMA). Other methacrylates include hioxifilcon
(48% water) and methafilcon (55% water) or even lidofilcon (70% water).
Desirable properties include being nontoxic, permeable to oxygen, comfortable to wear, and inexpensive. Also desirable is the ability to conform to the shape of the eye and to be easily cleaned (if not disposable).
c. Hard contact lenses are typically made of PMMA, a rigid non-gas permeable plastic. The soft contact lenses that replaced them are made of
silicone, which is flexible and allows oxygen to reach the eye. Because of these properties, the soft lenses tend to be more comfortable.

Acetone dissolves the polymer, which allows the gas of the foaming agent to escape, causing the polymer the collapse on itself and become more dense.

a. LDPE cannot be used in this application because it does not have the required strength.
b. To have the strength in this application, the HDPE molecules must line up in a way that produces the required strength, which the linear molecules allows the sufficient flexibility.

When plastic is stretched, the molecules become aligned parallel to each other and in the direction of the pull. This change in its structure is irreversible and if the pulling continues the plastic will break. When paper is pulled, the paper tears instead of stretching. The cellulose molecules in paper are held rigidly in place, thus they are not free to become aligned as in plastic.

a. The four properties are:
(1) stable over time of intended use
(2) non-toxic.
(3) Lack of solubility in body fluids
(4) Lack of reactivity in body fluids
b. Several types of polymers are commonly used. Polymethyl methacrylate (PMMA), fluoro-silicone-acrylate polymers and fluoro-silicones. Polymacon (38% water) is typical of the polymers used for soft lenses and is a polymer of 2-hydroxyethyl methacrylate (HEMA). Other methacrylates include hioxifilcon
(48% water) and methafilcon (55% water) or even lidofilcon (70% water).
Desirable properties include being nontoxic, permeable to oxygen, comfortable to wear, and inexpensive. Also desirable is the ability to conform to the shape of the eye and to be easily cleaned (if not disposable).
c. Hard contact lenses are typically made of PMMA, a rigid non-gas permeable plastic. The soft contact lenses that replaced them are made of
silicone, which is flexible and allows oxygen to reach the eye. Because of these properties, the soft lenses tend to be more comfortable.

a. Exothermic as heat is given out as it burns.
b. Endothermic as water gains energy to change phase from liquid to vapour.
c. Endothermic as it takes in energy for it to melt to overcome the intermolecular forces of attraction between the particles to change into liquid state.

Enthalpy change of reaction = sum of bond strength of bonds broken – sum of bond strength of bonds formed
A good explosion requires a highly exothermic reaction. Thus, the bonds of reactants should be weak and the relative bond strength of the product should be high.

Heat is the total energy of molecular motion in a substance but temperature is a measure of the average energy of molecular motion in a substance. Temperature does not depend on the size and type of the object, but heat does.

For example, the temperature of a small cup of water might be the same as the temperature of a large tub of water, but the tub of water has more heat because it has more water and thus more heat/thermal energy

a. As the reference standard for octane rating is 100, which refers to a gasoline containing pure iso-octane, the gasoline with 98 octane rating has the same knocking characteristics as a mixture of 98% iso-octane and 2% heptane.

b. Oxygenates are chemical compounds that contain oxygen but the octane rating only reflects the knocking characteristics of gasoline but not the chemical formula of it. So the octane rating does not tell us if the fuel contains oxygenates.