Answer:
pKa = 3.675
Explanation:
∴ <em>C</em> X-281 = 0.079 M
∴ pH = 2.40
let X-281 a weak acid ( HA ):
∴ HA ↔ H+ + A-
⇒ Ka = [H+] * [A-] / [HA]
mass balance:
⇒<em> C</em> HA = 0.079 M = [HA] + [A-]
⇒ [HA] = 0.079 - [A-]
charge balance:
⇒ [H+] = [A-] + [OH-]... [OH-] is negligible; it comes from to water
⇒ [H+] = [A-]
∴ pH = - log [H+] = 2.40
⇒ [H+] = 3.981 E-3 M
replacing in Ka:
⇒ Ka = [H+]² / ( 0.079 - [H+] )
⇒ Ka = ( 3.981 E-3 )² / ( 0.079 - 3.981 E-3 )
⇒ Ka = 2.113 E-4
⇒ pKa = - Log ( 2.113 E-4 )
⇒ pKa = 3.675
Answer:
Any matter considered to be a fuel contains chemical energy
Energy has to be provided to initiate the reaction.
So yes. It is
Answer:
d= 50.23 g/cm³
Explanation:
Given data:
radius = 137.9 pm
mass is = 5.5 × 10−22 g
density = ?
Solution:
volume of sphere= 4/3π r³
First of all we calculate the volume:
v= 4/3π r3
v= 1.33× 3.14× (137.9)³
v= 1.33 × 3.14 × 2622362.939 pm³
v= 1.095 × 10∧7 pm³
v= 1.095 × 10∧-23 cm³
Formula:
Density:
d=m/v
d= 5.5 × 10−22 g/ 1.095 × 10∧-23 cm³
d= 5.023 × 10∧+1 g/cm³
d= 50.23 g/cm³
An Ionic bond is when you have a metal and a nonmetal element bonded together. In this kind of bonds, the metal atom takes electrons from the nonmetal. on other words, this bond involves the gaining and losing of electrons. The atom that receives the electrons becomes an anion (negatively charged ion) and the one that loses them becomes the cation (positively charged ion)
A covalent bond is a bond created between two nonmetals element. In here, both atoms share the electrons.
Both bonds involve interaction between atoms.
