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>
Answer:
130.1 x 10²³ molecules of sugar
Explanation:
One dozen = 12 donuts
1 doughnut = 1.8 moles of sugar
12 doughnut = (1.8 x 12) moles of sugar = 21.6 moles of sugar
1 mole of any substance contains Avogadro’s number (6.023 x 10²³) of molecules.
1 mole of sugar = 6.023 x 10²³ molecules of sugar
21.6 moles of sugar = (6.023 x 10²³ x 21.6) molecules of sugar
= 130.1 x 10²³ molecules of sugar
Answer : The temperature in kelvins is, 
Explanation : Given,
= 178.5 KJ/mole = 178500 J/mole
= 161.0 J/mole.K
Gibbs–Helmholtz equation is :
As per question the reaction is spontaneous that means the value of 
is negative or we can say that the value of is less than zero.
The above expression will be:
Now put all the given values in this expression, we get :
Therefore, the temperature in kelvins is,
The answer is B plastic bags made from petroleum.
