Matter is the basic unit of every thing in the world, whether living or nonliving. So, it is logical to set definitions and postulates because these could pave way to other complexities of science. It is the foundation of science. That is why theories and laws are formulated for matter such as: Kinetic Theory of Matter, Dalton's Atomic Model, Newton's Law of Motion, Conservation Laws and many more.
Oceans :unusable
Rivers :usable
Glaciers :usable
Freshwater: usable
Lakes :usable
Groundwater :usable
To calculate electronegativity, start by going online to find an electronegativity table. You can then assess the quality of a bond between 2 atoms by looking up their electronegativities on the table and subtracting the smaller one from the larger one. If the difference is less than 0.5, the bond is nonpolar covalent.
The pressure in a sealed container means the volume of container is fixed
so we cannot change the volume of container hence gas
The other factors which can affect the pressure are
a) moles of gas : if we increase the moles of gas the pressure of gas will increase
b) Temperature: if we increase the pressure of gas the pressure of gas will increase due to increase in kinetic energy
So the following cannot increase pressure
a) decrease in moles of gas
b) decrease in temperature of gas