Cloning gives the exact same dog everytime. As it might give undesirable results and no new characteristic trait will be found. So genetically no improvement in breed, whereas breeding might lead to beneficial variations.

2 pros – 1) Cheaper and can grow in harsh conditions.
2) More nutritious and more resistant.
2 cons – 1) Allergic reactions
2) Political cost and health issues.

Acetone dissolves the polymer, allowing gas of foaming agent to escape. This polymer collapses on itself and is more dense because the gas has been removed

a. A LDPE does not have the required strength.
b. HDPE molecules must line up in a way that produces the required strength. Using this film of HDPE allows sufficient flexibility.

The plastic molecules become aligned parallel to each other and in the direction of the pull. This alteration of the 3-D structure is not reversible. The paper will tear if pulled because the molecules are held more rigidly in place, and are not free to be aligned,which implies that the molecular interactions in paper is stronger.

a. They are – Stable over time, Non – toxic , lack of reactivity with body fluids and have appropriate permeability and process-ability for designed application.

b. PMMA(plexiglas) hard lenses.
Rigid gas permeable.
Hydrogel-polymacon.
Silicone hydrogel.

c. Hard contact lens :
PMMA, excellent optical qualties, durability and biocompatibility but no oxygen permeability.

Soft lens:
hydrogel, water – retaining and permeability of oxygen.

1) 2 ways carbon atom differ from another:
– Isotopes (number of neutrons)
– Number of electrons (when involved in bonding)

2) 3 Ways carbon atoms differ from uranium atoms
– Number of protons
– Number of neutrons
– Size of nuclei (atomic mass)

They show that they are isotopes with 7 and 8 neutrons respectively, while atomic number is the same.
It gives us more information on its chemical reactivity.

a) 94
b) Neptunium – 93 protons
Plutonium – 94 protons
c) 86

E – fuel rods
D – cooling water into the core
B – cooling water out of the core
A – control rod assembly
C – control rods

The techniques mainly used nowadays are reverse osmosis and distillation. Both of these techniques require a lot of energy and is thus, expensive to use. It is cheaper to find freshwater and then transport it out. Thus, desalination techniques is not widely used as it is not economic and efficient-friendly.

Water-soluble vitamins are polar and fat-soluble vitamins are non-polar compounds. This is because ‘like dissolves like’. Water is polar and therefore water-soluble vitamins are polar.

a) Instead of using a dryer, it helps to reduce the electricity usage.
b) Instead of driving, it helps to reduce carbon oxides, nitrogen oxides and sulphur oxides emissions.
c) This will help to reduce electricity consumption when the dishwashers and washing machines are run with bigger loads.
d) The insulation will help to keep the water hot, thus reducing electricity consumption.
e) This is reduce the need for transportation of the food, thus reducing carbon oxides, nitrogen oxides and sulphur oxides emissions.

a)Coal fired plants will churn out smoke and small droplets of SO3, which leads to poor visibility
b)The pH is around 4.5. The pH of natural rain is 5.5. And since the rain is 10 times more acidic, it’s pH is 1 unit lower.

a. exothermic reaction – charcoal gives off heat when burned.
b. endothermic reaction – water takes in heat to evaporate, from liquid to gaseous state.
c. endothermic reaction – ice absorbs heat to melt from solid to liquid state.

The bonds within the reactants are weak in a highly exothermic reaction while those within the products are strong. The energy needed to break the bonds within the reactants is small as less energy is needed to overcome weak bonds. This thus leads to negative net energy change.

Temperature – the average measure of heat energy with respect to movement of molecules. Temperature determines the direction of heat flow.
Heat – energy flowing from a hotter to colder object

eg. you can set the temperature of a room to hotter or colder.
when you touch a hot vessel, you can feel the heat.

a. As the octane reading is 98, it has the same knocking characteristics as a mixture that contains 98% octane, therefore it is more resistant to knocking than gasoline with lower octane reading.

b. The octane rating does not say anything about whether the fuel contains oxygenates. Other labels provide that information.