The composition of PBS is 0.137M, NaCL, 0.012M Phosphate,0.0072M KCL, PH7.4.Below is the protocol of making 1x liter 10x concentrate PBS:combine the following 80g NaCL 2g KCL,14.4g Na, HPO,2.4g KHPO4,800mil distilled water.1)adjust ph to 7.4 with HCL 2)Add H2O to 1 liter 3)autoclave for 20minutes on a liquid cycle. store at room temperature

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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)

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-

b. examine and describe cells