Dmitri Mendeleev is the scientist who first developed the periodic table.
He is a Russian chemist and inventor who formulated the periodic law and created the periodic table of elements. He corrected some of the properties of the elements. Now, we can easily locate the elements we wanted to identify. With the help of Mendeleev, studying chemistry is not that difficult because he tried to simplify some of the concept that was complex before.
Answer:
Ka = 6.02x10⁻⁶
Explanation:
The equilibrium that takes place is:
We <u>calculate [H⁺] from the pH</u>:
- [H⁺] =
Keep in mind that [H⁺]=[A⁻].
As for [HA], we know the acid is 0.66% dissociated, in other words:
We <u>calculate [HA]</u>:
Finally we <u>calculate the Ka</u>:
- Ka =
![\frac{[9.12x10^{-4}]*[9.12x10^{-4}]}{[0.138]}](https://tex.z-dn.net/?f=%5Cfrac%7B%5B9.12x10%5E%7B-4%7D%5D%2A%5B9.12x10%5E%7B-4%7D%5D%7D%7B%5B0.138%5D%7D)
= 6.02x10⁻⁶
Answer:
7 hours
Explanation: step 1. 160x4=640
step 2. 1180-640=540
step 3. 540÷180=3
step 4. 3+4=7
Answer:
The word radon is derived from radium, of which radon is gas. Early in its discovery it was also called radium emanation and niton, which comes from the Latin nitens, Since 1923, however, it has been called radon.
It is energetically favorable for all atoms to have a complete outer
electron shell. Loosely, the atoms on the left hand side of the periodic
table only have a few extra electrons in their outer shell so it is
energetically favorable for them to lose them. The atoms on the right
hand side of the periodic table almost have enough electrons in their
outer shell and so they have a tendency to gain them.
Once electrons have left an electron shell, an atom will have a positive
charge because it has more protons (positive charges) than electrons
(negative charges). Similarly, an electron which has gained electrons to
complete its outer shell will have a negative charge because it now has
more electrons (negative charge) than protons (positive charge).
