Beryllium (Be): 1sC2sD, what's C and D?
2 answers:
Answer:
C is equal to 2 and D is equal to 2.
Explanation:
Here C and D represents number of electrons in 1s and 2s orbitals.
Be has 4 electrons. Now, in order write electronic configuration of an atom, electron filling should be started from orbital with lowest energy.
Energy order of orbital with increasing energy: 1s< 2s< 2p< 3s< 3p< 4s< 3d....
So, filling of electron should start from 1s orbital then 2s, 2p, 3s, 3p and so on.
Each orbital can have maximum of 2 electrons.
So electronic configuration of Be is:
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Given :
Molarity of sulfuric acid solution is 3.0 M.
Amount of sulfuric acid present in solution is 9.809 g.
To Find :
The volume of solution.
Solution :
We know, molarity is given by :
Therefore, volume required is 33.33 ml .
Answer:
pH ≅ 4.80
Explanation:
Given that:
the volume of HN₃ = 25 mL = 0.025 L
Molarity of HN₃ = 0.150 M
number of moles of HN₃ = 0.025 × 0.150
number of moles of HN₃ = 0.00375 mol
Molarity of NaOH = 0.150 M
the volume of NaOH = 13.3 mL = 0.0133
number of moles of NaOH = 0.0133× 0.150
number of moles of NaOH = 0.001995 mol
The chemical equation for the reaction of this process can be written as:
1 mole of hydrazoic acid react with 1 mole of hydroxide to give nitride ion and water
thus the new number of moles of HN₃ = 0.00375 - 0.001995 = 0.001755 mol
Total volume used in the reaction = 0.025 + 0.0133 = 0.0383 L
Concentration of =
= 0.0458 M
Concentration of =
= 0.0521 M
GIven that :
Ka =
Thus; it's pKa = 4.72
pH ≅ 4.80