Alkanes are saturated hydrocarbon, that is they contain hydrogen and carbon without a double or triple bond between the carbon atoms, e.g. ethane, propane. Group 7a in the periodic table are called halogens e.g chlorine, bromine. Alkanes react with halogens in a reaction called substitution, where halogens replace hydrogen atoms in alkanes.
An earthquake is a catastrophic<span> event that results from a gradual accumulation of stresses at fault lines. Clearly </span>catastrophism<span> is at work.</span>
Chemical reactions that release energy will not occur without a source of energy. So the answer is release.
Answer: 72 grams of
are needed to completely burn 19.7 g 
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number
of particles.
To calculate the number of moles, we use the equation:

Putting in the values we get:


According to stoichiometry:
1 mole of
requires 5 moles of oxygen
0.45 moles of
require=
moles of oxygen
Mass of 
72 grams of
are needed to completely burn 19.7 g 
This is because amino group of p-aminobenzoic acid is an aniline and is less electrophilic than an alkyl amine.
<h3>What is an Aniline?</h3>
This is an aromatic amine which consists of a phenyl group attached to an amino group.
The amino group of p-aminobenzoic acid being an aniline makes it less electrophilic which is why an alkyl amine participates in the reaction instead.
Read more about Aniline here brainly.com/question/9982058