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:
T₁ = 135.41 K
Explanation:
Given data:
Initial pressure = 1.12 atm
Finial temperature = 36.5 °C (36.5 +273 = 309.5 K)
Initial temperature = ?
Final pressure = 2.56 atm
Formula:
P₁/T₁ = P₂/T₂
P₁ = Initial pressure
T₁ = Initial temperature
P₂ = Final pressure
T₂ = Final temperature
Solution:
P₁/T₁ = P₂/T₂
T₁ = P₁T₂ /P₂
T₁ = 1.12 atm × 309.5 K / 2.56 atm
T₁ = 346.64 atm . K / 2.56 atm
T₁ = 135.41 K
Burning splint test
2H2 (g) + O2 (g) -> 2H20 (g) + heat
It’s a combustion reaction
Answer:
447,25k
Explanation:
According to the ideal gas law

Where:
P: is the pressure of the gas in atmospheres.
V: is the volume of the gas in liters.
n: number of moles of the gas
R: ideal gas constant
T: absolute temperature of the gas in kelvin
now using:
