Answer: The gas phase is unique among the three states of matter in that there are some simple models we can use to predict the physical behavior of all gases—independent of their identities. We cannot do this for the solid and liquid states. ... Gas particles do not experience any force of attraction or repulsion with each other.
Explanation:
Answer : The type of reaction described in the sentence is Synthesis or Combination
Explanation :
The balanced equation for the reaction between Phosphorous and Oxygen gas can be written as

From the above equation we can see that there are two different reactants ( P and O₂ ) which are combining with each other to give a single product.
This type of reaction is known as Combination or Synthesis.
A general form of Synthesis reaction is given below.

Here we can conclude that a synthesis / combination reaction is the one where 2 or more reactants combine together to give only one product .
Answer:
See explanation
Explanation:
Polymerization is the process whereby two or more monomers link together to form a compound of high molecular mass called a polymer.
There are two kinds of polymers;
-Addition polymers
-Condensation polymers
Addition polymers are formed by the joining of two or more monomers to form a polymer without the elimination of a small molecule.
Condensation polymers are formed by the joining of two or more molecules to form polymers with the elimination of a small molecule.
The main difference between polyethene and polyester is that polyethene is an addition polymer while polyester is a condensation polymer.
In polyethene, ethene molecules are joined together having the repeating unit as [-CH2-CH2-]n.
In polyester, the polymer arises from the reaction of carboxylic acid and an alcohol and loss of water molecules.
The mass numbers of the different isotopes of that element are averaged according to their respective abundances in nature.