Answer:
Concentration: 0.185M HX
Ka = 9.836x10⁻⁶
pKa = 5.01
Explanation:
A weak acid, HX, reacts with NaOH as follows:
HX + NaOH → NaX + H2O
<em>Where 1 mole of HX reacts with 1 mole of NaOH</em>
To solve this question we need to find the moles of NaOH at equivalence point (Were moles HX = Moles NaOH).
18.50mL = 0.01850L * (0.20mol / L) = 0.00370 moles NaOH = Moles HX
In 20.0mL = 0.0200L =
0.00370 moles HX / 0.0200L = 0.185M HX
The equilibrium of HX is:
HX(aq) ⇄ H⁺(aq) + X⁻(aq)
And Ka is defined as:
Ka = [H⁺] [X⁻] / [HX]
<em>Where [H⁺] = [X⁻] because comes from the same equilibrium</em>
As pH = 2.87, [H+] = 10^-pH = 1.349x10⁻³M
Replacing:
Ka = [H⁺] [H⁺] / [HX]
Ka = [1.349x10⁻³M]² / [0.185M]
Ka = 9.836x10⁻⁶
pKa = -log Ka
<h3>pKa = 5.01</h3>
Molecule, a group of two or more atoms that form the smallest identifiable unit into which a pure substance can be divided and still retain the composition and chemical properties of that substance.
While Atoms are single neutral particles,
Molecules are neutral particles made of two or more atoms bonded together.
Exaplmes for molecules
H2O (water)
N2 (nitrogen)
O3 (ozone)
CaO (calcium oxide)
C6H12O6 (glucose, a type of sugar)
NaCl (table salt
And examples for atoms
Neon (Ne)
Hydrogen (H)
Argon (Ar)
Iron (Fe)
Calcium (Ca)
Deuterium, an isotope of hydrogen that has one proton and one neutron.
Plutonium (Pu)
F-, a fluorine anion.
Answer:
hydrogen bonding
Explanation:
The two strands of DNA are held together by hydrogen bonds between complimentary nucleotides.
Physical change
Giddy Up!!!!!
