What is the most efficient way to make up a hepes buffer at ph 8.5?

value of HEPES is 7.5.

A proper amount of HEPES is mixed with distilled water (sterilized) to avoid any contamination. After that, check the pH with the help of pH scale or pH meter.

First, take the basic form of HEPES and then add hydrochloric acid drop by drop to bring down the pH at 8.5.

When pH reaches 8.5; the buffer solution is filtered and placed in the  glass container and then covered by aluminium foil.

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.