Answer:
Kₐ = 6.7 x 10⁻⁴
Explanation:
First lets write the equilibrium expression, Ka , for the dissociation of hydrofluoric acid:
HF + H₂O ⇄ H₃O⁺ + F⁻
Kₐ = [ H₃O⁺ ] [ F⁻ ] /[ [ HF ]
Since we are given the pH we can calculate the [ H₃O⁺ ] ( pH = - log [ H₃O⁺ ] , and because the acid dissociates into a 1: 1 relation , we will also have [F⁻ ]. The [ HF ] is given in the question so we have all the information that is needed to compute Kₐ.
pH = -log [ H₃O⁺ ]
1.68 = - log [ H₃O⁺ ]
Taking antilog to both sides of this equation:
10^-1.68 = [ H₃O⁺ ] ⇒ 2.1 X 10⁻² M= [ H₃O⁺ ]
[ F⁻ ] = 2.1 X 10⁻² M
Solving for Kₐ :
Kₐ = ( 2.1 X 10⁻² ) x ( 2.1 X 10⁻² ) / 0.65 = 6.7 x 10⁻⁴
(Rounded to two significant figures, the powers of 10 have infinite precision )
Answer:
9.4 liter
Explanation:
1) Data:
V₁ = 10.0 L
T₁ = 25°C = 25 + 273.15 K = 298.15 K
P₁ = 98.7 Kpa
T₂ = 20°C = 20 + 273.15 K = 293.15 K
P₂ = 102.7 KPa
V₂ = ?
2) Formula:
Used combined law of gases:
PV / T = constant
P₁V₁ / T₁ = P₂V₂ / T₂
3) Solution:
Solve the equation for V₂:
V₂ = P₁V₁ T₂ / (P₂ T₁)
Substitute and compuite:
V₂ = P₁V₁ T₂ / (P₂ T₁)
V₂ = 98.7 KPa × 10.0 L × 293.15 K / (102.7 KPa × 298.15 K)
V₂ = 9.4 liter ← answer
You can learn more about gas law problems reading this other answer on
Explanation:
A forest would have have the most fertile soil
Answer:
The seven SI base units, which are comprised of:
Length - meter (m)
Time - second (s)
Amount of substance - mole (mole)
Electric current - ampere (A)
Temperature - kelvin (K)
Luminous intensity - candela (cd)
Mass - kilogram (kg)
Explanation: