Answer:
1st answer: A. nitrogen
2nd answer: A. Sodium carbonate
Explanation:
Explanation:
Le Chatelier's principle states that for a long period of time if a system is at equilibrium and it is subjected to change in concentration, temperature, volume or pressure then the system shifts to a new equilibrium.
This change will partly counter acts the applied change.
Therefore, when heat is added to the system then equilibrium will shift to the side where temperature or heat is reduced again.
For example, 
Since heat is added to the system, hence, system will shift to the left side or we can say equilibrium will shift to the backward direction.
The answer is Ka = 1.00x10^-10.
Solution:
When given the pH value of the solution equal to 11, we can compute for pOH as
pOH = 14 - pH = 14 - 11.00 = 3.00
We solve for the concentration of OH- using the equation
[OH-] = 10^-pOH = 10^-3 = x
Considering the sodium salt NaA in water, we have the equation
NaA → Na+ + A-
hence, [A-] = 0.0100 M
Since HA is a weak acid, then A- must be the conjugate base and we can set up an ICE table for the reaction
A- + H2O ⇌ HA + OH-
Initial 0.0100 0 0
Change -x +x +x
Equilibrium 0.0100-x x x
We can now calculate the Kb for A-:
Kb = [HA][OH-] / [A-]
= x<span>²</span> / 0.0100-x
Approximating that x is negligible compared to 0.0100 simplifies the equation to
Kb = (10^-3)² / 0.0100 = 0.000100 = 1.00x10^-4
We can finally calculate the Ka for HA from the Kb, since we know that Kw = Ka*Kb = 1.0 x 10^-14:
Ka = Kw / Kb
= 1.00x10^-14 / 1.00x10^-4
= 1.00x10^-10
Carbon will have 4 valence electrons. It will have 2 in the p orbital and 2 in the s orbital. You can see this when you find the noble gas configuration of carbon which is [He]2s²2p² showing that carbon has 4 valence electrons.
I hope this helps. Let me know if anything is unclear.
