Answer: Positive environmental changes.
Explanation: Without many humans around, the environment has been getting better as more sea life have been spotted in places they haven't been for decades, as well as clearer waters and less rubbish about. Pollution levels have dropped as there are barley any planes in the sky and not many cars about.
Answer:
honestly,i can say that socially being away from people reduces stress
Explanation:
A chemist titrates of a butanoic acid solution with solution at . Calculate the pH at equivalence. The of butanoic acid is__________ .Round your answer to decimal places.
Note for advanced students: you may assume the total volume of the solution equals the initial volume plus the volume of solution added.
Answer:
pH = 8.75
Explanation:
100.0mL of a 0.8108M of a butanoic acid (HC₃H₇CO₂, pKa 4.82) solution is titrated with 0.0520M KOH.
The reaction is:
HC₃H₇CO₂ + KOH → H₂O + KC₃H₇CO
Moles of butanoic acid are:
0.1000L × (0.8108mol / L) = 0.08108 moles of butanoic
For a complete reaction, volume of KOH must be added is the volume in which 0.08108 moles of KOH are added, that is:
0.08108 mol × (L / 0.0520mol) = 1.56L of KOH.
Total volume in equilibrium is 1.56L + 0.10L = 1.66L
That means concentration of butanoic acid is:
0.08108 mol / 1.66L = 0.04884M HC₃H₇CO₂
At equivalence point, there is just C₃H₇CO⁻ in solution
Kb of butanoic acid is:
C₃H₇CO⁻ + H₂O ⇄ HC₃H₇CO₂ + OH⁻
Kb = Kw / Ka
Ka = 10^-pKa
Ka = 1.51x10⁻⁵
Kb = 1x10⁻¹⁴ / 1.51x10⁻⁵ = 6.61x10⁻¹⁰
The equilibrium of Kb is:
Kb = 6.61x10⁻¹⁰ = [HC₃H₇CO₂] [OH⁻] / [C₃H₇CO⁻]
As at equivalence point there is just C₃H₇CO⁻, the equilibrium concentrations are:
[C₃H₇CO⁻] = 0.04884M - X
[HC₃H₇CO₂] = X
[OH⁻] = X
Replacing in Kb:
6.61x10⁻¹⁰ = X² / [0.04884M - X]
0 = X² + 6.61x10⁻¹⁰X - 3.23x10⁻¹¹
Solving for X:
X = -5.68x10⁻⁶ → False solution. There is no negative concentrations
X = 5.683x10⁻⁶ → Right solution.
As [OH⁻] = X, [OH⁻] = 5.683x10⁻⁶.
pOH = - log [OH⁻]
pOH = 5.245
pH = 14 - pOH
pH = 8.75Which of the following is evidence for a physical change? A) burning B) fizzing C) evaporating D) rusting
Answer:c
Explanation: rusting, burning and fuzzing are all examples of chemical reactions/changes.
what is the balanced equation for calcium sulfate?
Answer:
CaSO4
Explanation:
Calcium sulfate (or calcium sulphate) is the inorganic compound with the formula CaSO4 and related hydrates.