One carbon atom can differ from another in the number of neutrons or electrons. (Example: C-12, C-13)
All carbon atoms differ from all uranium atoms in their number of protons, neutrons and electrons.

The superscript represents the mass number.
Mass number refers to the number of protons and neutrons altogether.
14N has the mass number of 14 while 15N has the mass number of 15.

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

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

Desalination is not widely used as a method to produce potable drinking water because:
1. the plant is expensive to build
2. not energy-efficient; expensive to operate
3. produces much less water than needed

The water-soluble vitamins are polar compounds since they can dissolve in water which is a polar solvent.
The fat-soluble vitamins are non-polar as they do not mix well with water, which is a polar solvent.

a. Reduce need for use of dryer, cut down use of energy and electricity; this in turn reduced the need for coals to be burned

b. Conserves energy and cuts down on the emissions of nitrogen oxides which contributes to acid rain

c. Conserves water and reduces electrical consumption

d. Reduces energy use by preventing heat and cold from escaping

e. Reduce transportation related acid-rain emissions (NO2, SO2) being released into the atmosphere.

a)
Coal fired plants releases huge amounts of small droplets of sulfur trioxide (SO3) during combustion. The SO3 water droplets become visible as fog.
b)
Acid level is 10 times stronger = 1 pH difference
If the pH level of natural rain is 5.3, the estimated pH of rainfall in the park is 4.3.