Which of the following is not considered a branch of chemistry?
organic chemistry
biochemistry
analytical chemistry
inorganic chemistry
physical chemistry
pure chemistry

how many significant digits are in the number 0.0001305?
3
4
7
8

pure chemistry

4

Explanation:

It is the consideration of the facts and theories of chemistry in their purely scientific relations. Therefore it is not considered to be a branch of chemistry because it doesn't necessarily refer to their practical application or mere utility.

hope this

explanation:

covalent bonds

consist of pairs of electrons shared by two atoms, and bind the atoms to fixed orientation and requre high energies to break them

ionic bonds

when two atoms differ considerably in their electronegativity, then one of the atoms will lose its electron to the other atom. this results in a positively charged ion(cation) and a negatively charged ion (anion)