The valence level of an atom refers to the number of electrons that reside in the upper most energy level. Nitrogen has an atomic number of 7 and therefore has 7 electrons. The first energy level (1) holds 2 electrons, leaving 5 electrons to reside in the second energy level (2s and 2p). Therefore the valence of nitrogen is 5.
Answer: The value of
is 0.0012 M and
is
.
Explanation:
pH is the negative logarithm of concentration of hydrogen ion.
It is given that pH is 2.89. So, the value of concentration of hydrogen ions is calculated as follows.
![pH = - log [H^{+}]\\2.89 = - log [H^{+}]\\conc. H^{+} = 0.0012 M](https://tex.z-dn.net/?f=pH%20%3D%20-%20log%20%5BH%5E%7B%2B%7D%5D%5C%5C2.89%20%3D%20-%20log%20%5BH%5E%7B%2B%7D%5D%5C%5Cconc.%20H%5E%7B%2B%7D%20%3D%200.0012%20M)
The relation between pH and pOH value is as follows.
pH + pOH = 14
0.0012 + pOH = 14
pOH = 14 - 0.0012 = 13.99
Now, pOH is the negative logarithm of concentration of hydroxide ions.
Hence,
is calculated as follows.
![pOH = - log [OH^{-}]\\13.99 = - log [OH^{-}]\\conc. OH^{-} = 1.02 \times 10^{-14} M](https://tex.z-dn.net/?f=pOH%20%3D%20-%20log%20%5BOH%5E%7B-%7D%5D%5C%5C13.99%20%3D%20-%20log%20%5BOH%5E%7B-%7D%5D%5C%5Cconc.%20OH%5E%7B-%7D%20%3D%201.02%20%5Ctimes%2010%5E%7B-14%7D%20M)
Thus, we can conclude that the value of
is 0.0012 M and
is
.
1) Solids have a fixed shape
The particles of solids are held into their positions and are only able to vibrate about fixed points. The strength of the bonding means that the particles have their own shape, which they retain, and do not take the form of the container they are in.
2) Solids may not flow
The molecules of liquids are able to slide past one another due to weaker bonds between particles. This allows the liquid to flow; whereas, this movement is not possible in solids so they cannot flow.
3) Solids may fracture
The fact that solids possess a rigid structure means that they have the ability to fracture. Although some are able to withstand more stress than others, all solids may break. This breakage occurs when the intermolecular bonds are mechanically broken. This is not possible in the case of liquids because such rigid intermolecular bonds do not exist.
PH = pKa + log
![\frac{[base]}{[Acid]}](https://tex.z-dn.net/?f=%20%5Cfrac%7B%5Bbase%5D%7D%7B%5BAcid%5D%7D%20)
Acid is HC₂H₃O₂ and conjugate base is KC₂H₃O₂,
pKa = - log Ka = - log (1.8 x 10⁻⁵) = 4.74
so pH = 4.74 + log (0.2/0.2) = 4.74
This is called maximum buffer capacity (when acid conc. and base conc. are equal) the pH = pKa in this case
Explanation:
The given reaction at cathode will be as follows.
At cathode:
,
= -0.761 V
At anode:
,
= 0.761
Therefore, net reaction equation will be as follows.

Initial: 0.129 - - 0.427
Change: -0.047 - - -0.047
Equilibrium: (0.129 - 0.047) (0.427 - 0.047)
= 0.082 = 0.38
As
for the given reaction is zero.
Hence, equation for calculating new cell potential will be as follows.
E_{cell} = ![E^{o}_{cell} - \frac{RT}{nF} ln \frac{[Zn^{2+}]_{products}}{[Zn^{2+}]_{reactants}}](https://tex.z-dn.net/?f=E%5E%7Bo%7D_%7Bcell%7D%20-%20%5Cfrac%7BRT%7D%7BnF%7D%20ln%20%5Cfrac%7B%5BZn%5E%7B2%2B%7D%5D_%7Bproducts%7D%7D%7B%5BZn%5E%7B2%2B%7D%5D_%7Breactants%7D%7D)
= 
= 0.019
Thus, we can conclude that the cell potential of the given cell is 0.019.