When dissolved in water, acids donate hydrogen ions (H+). Hydrogen ions are hydrogen atoms that have lost an electron and now have just a proton, giving them a positive electrical charge. ... If a solution has a high concentration of H+ ions, then it is acidic.
A chemical formula shows the kinds and numbers of <u>atoms</u> in the smallest representative unit of a substance.
<u>Explanation:</u>
In chemistry, a formula unit is the empirical formula of "ionic or covalent network solid compound" that is used as an independent entity for "stoichiometric calculations". This formula is a representation of a molecule that uses chemical symbols.
The unit is the lowest whole number ratio of ions represented in an ionic compound. It gives the numbers of atoms representing the "smallest representative" unit of a substance. The number of atoms also tells us about the chemical and physical properties of the compound formed.
Answer:
a) 
b) entropy of the sistem equal to a), entropy of the universe grater than a).
Explanation:
a) The change of entropy for a reversible process:


The energy balance:
![\delta U=[tex]\delta Q- \delta W](https://tex.z-dn.net/?f=%5Cdelta%20U%3D%5Btex%5D%5Cdelta%20Q-%20%5Cdelta%20W)
If the process is isothermical the U doesn't change:
![0=[tex]\delta Q- \delta W](https://tex.z-dn.net/?f=0%3D%5Btex%5D%5Cdelta%20Q-%20%5Cdelta%20W)


The work:

If it is an ideal gas:


Solving:

Replacing:


Given that it's a compression: V2<V1 and ln(V2/V1)<0. So:

b) The entropy change of the sistem will be equal to the calculated in a), but the change of entropy of the universe will be 0 in a) (reversible process) and in b) has to be positive given that it is an irreversible process.
The answer is gonna be the last one :)
<span>entropy = heat energy (q) /Temperature(T)
can u now answer it </span>