Carbon atoms differ in terms of:
1. The number of neutrons (For example, C-12, C-13)
2. The number of electrons (The atoms would form ions)

While all carbon atoms differ from all uranium atoms in terms of:
1. The number of protons (Uranium has 92 protons while Carbon has 6 protons)
2. The number of neutrons
3. The number of electrons
2. Chemical properties (For example, electronegativity)

Symbol N represents nitrogen and stands for the naturally occurring mixture of all isotopes.
Symbol 14N and 15N represent specific isotopes with mass number of 14 and 15 respectively.

a. There are 94 protons in the isotope.

b. Neptunium has 93 protons and Plutonium has 94 protons.

c. Radon-222 has 86 protons. Isotopes only differ in mass number but not proton number.

A: Control rods
B: Cooling water out of the core
C: Control rod assembly
D: Cooling water into the core
E: Fuel rods

The techniques used for the desalination of water is distillation and reverse osmosis. However, both require a lot of energy in the process. For instance, reverse osmosis utilizes high pressure to push water molecules through a semipermeable membrane from a region of low water concentration to high water concentration. Therefore, the processes are very costly.

The processes are also impractical for large scale desalination. Greenhouse gases are emitted in the process, causing the processes not to be environmentally sustainable. The large energy consumption requirement also makes large scale production difficult.

Solubility follows the rule “like dissolves like”.

Therefore, polar compounds will be soluble in polar solvents such was water, while non-polar compounds will be soluble in non-polar solvents like fat.

Vitamins that are water-soluble are polar whereas vitamins that are fat-soluble are non-polar.

(a) Using the dryer to dry your clothes uses electricity and produces acid rain.

(b) Driving a car will result in vehicle exhaust that produces more Sox and Nox.

(c) This reduces the number of times we need to run the washing machine to clean all the dishes, reducing acid rain.

(d) Insulated hot water heaters and pipes are able to keep the water for a longer time, reducing electricity consumption and reducing acid rain.

(a) Coal-fired plants release huge amounts of water vapour. When water vapour cools down, it becomes visible as fog, resulting in poor visibility for everyone.

(b)

Natural pH = 7
Acidic level is 10 times stronger than normal, pH level drops by 1
pH of rainfall =6

a) Exothermic – the charcoal burns the skin and gives out heat

b) Endothermic – the skin feels cooler when water (like sweat) evaporates from the skin

c) Endothermic – the ice takes in heat to become water, which is an endothermic process

The reactants should have very weak bonds and the products should have very strong bonds. The greater the energy difference between the products and reactants, the more vigorous the reaction as more energy is released.

Heat is the transfer of energy from a hotter object to a cooler object, while temperature is the absolute amount of energy possessed by the object.

For example, heat is the steam given off by a cooking pot, which can cook an egg, but temperature is a measurement of how hot the steam is.

a) An octane rating of 98 means that the gasoline has a knocking characteristic of 98% isooctane and 2% heptane. Isooctane has a lower boiling point than heptane and has a lower tendency to cause “knocking” in the engine. Therefore, gasoline with an octane rating of 98 would suggest a low tendency to cause knocking, and burns more smoothly.

b) The octane rating gives no clear indication of whether the fuel contains oxygenates. Examples of oxygenates include, MTBE, ETBE, methanol and ethanol. However, oxygenates enhance the octane number of the gasoline, assists combustion, reduces CO emissions and reduces knocking. Therefore, a high octane rating of 98 suggests that the gasoline does contain oxygenates, producing premium gasoline.