Answer:
a. pka = 3,73.
b. pkb = 10,27.
Explanation:
a. Supposing the chemical formula of X-281 is HX, the dissociation in water is:
HX + H₂O ⇄ H₃O⁺ + X⁻
Where ka is defined as:
![ka = \frac{[H_3O^+][X^-]}{[HX]}](https://tex.z-dn.net/?f=ka%20%3D%20%5Cfrac%7B%5BH_3O%5E%2B%5D%5BX%5E-%5D%7D%7B%5BHX%5D%7D)
In equilibrium, molar concentrations are:
[HX] = 0,089M - x
[H₃O⁺] = x
[X⁻] = x
pH is defined as -log[H₃O⁺]], thus, [H₃O⁺] is:
![[H_3O^+]} = 10^{-2,40}](https://tex.z-dn.net/?f=%5BH_3O%5E%2B%5D%7D%20%3D%2010%5E%7B-2%2C40%7D)
[H₃O⁺] = <em>0,004M</em>
Thus:
[X⁻] = 0,004M
And:
[HX] = 0,089M - 0,004M = <em>0,085M</em>
![ka = \frac{[0,004][0,004]}{[0,085]}](https://tex.z-dn.net/?f=ka%20%3D%20%5Cfrac%7B%5B0%2C004%5D%5B0%2C004%5D%7D%7B%5B0%2C085%5D%7D)
ka = 1,88x10⁻⁴
And <em>pka = 3,73</em>
b. As pka + pkb = 14,00
pkb = 14,00 - 3,73
<em>pkb = 10,27</em>
I hope it helps!
18.4 * 10^9 lbs = (18.4 * 10^9)/2000 tons
Cost = ((18.4 * 10^9)/2000 ) * 318
Cost = $ 2925600000
Cu = 63.546
N= 14.001 g/mol
O= 15.999 g/mol * 3 = 47.997
Copper (II) Nitrate has a MW of 125.544 g/mol
6.25 x 125.544
= 784.65 <--- is your answer, if there were was a multiple choice or not :)
One mole any substance contains 6.022 ₓ 10²³ particles called Avogadro's Number.
The relation between moles and number of particles is given as,
# of particles = moles ₓ Avogadro's number
In our case the particles are formula units of MgCO₃. So, 1 mole of MgCO₃ contain 6.022 ₓ 10²³ formula units, then the number of formula units in 1.72 moles are calculated as,
# of formula units = 1.72 mol ₓ 6.022 ₓ 10²³ formula units / mol
# of formula units = 1.035 ₓ 10²⁴ Formula Units
