Answer:
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Explanation:
Since sulfuric acid, H₂SO₄, is a diprotic acid and potassum hydroxide, KOH, contains one OH⁻ in the formula, the number of moles of potassium hydroxide must be twice the number of moles of sulfuric acid.
<u>1. Determine the number of moles of KOH in 47mL of 0.39M potassium hydroxide solution</u>
- number of moles = molarity × volume in liters
- number of moles = 0.39M × 47mL × 1liter/1,000 mL = 0.1833mol
<u>2. Determine the number of moles of sulfuric acid needed</u>
- number of moles of H₂SO₄ = number of moles of KOH/2 = 0.1833/2 = 0.009165mol
<u>3. Determine the concentration that contains 0.009165 mol in 25mL of the acid.</u>
- Molarity = number of moles / volume in liters
- M = 0.009165mol/(25mL) × (1,000mL/liter) = 0.3666M
Round to two significant figures: 0.37M
Answer: 2) Chloroform & Caustic potash
Explanation:
The carbylamine reaction is a kind of chemical test which is done to detect primary amines in an unknown solution. It cannot detect secondary and tertiary amines.
The reaction involves the heating with up of the unknown solution with alcoholic potassium hydroxide or caustic potash and the chloroform.
In the presence of primary amine, the production of isocyanide results.
Answer is: pH of aniline is 9.13.<span>
Chemical reaction: C</span>₆H₅NH₂(aq)+
H₂O(l) ⇌ C₆H₅NH₃⁺(aq) + OH⁻(aq).
pKb(C₆H₅NH₂) = 9.40.
Kb(C₆H₅NH₂) = 10∧(-9.4) = 4·10⁻¹⁰.
c₀(C₆H₅NH₂) = 0.45 M.
c(C₆H₅NH₃⁺) = c(OH⁻) = x.
c(C₆H₅NH₂) = 0.45 M - x.
Kb = c(C₆H₅NH₃⁺) · c(OH⁻) / c(C₆H₅NH₂).
4·10⁻¹⁰ = x² / (0.45 M - x).
Solve quadratic equation: x = c(OH⁻) = 0.0000134 M.
pOH = -log(0.0000134 M.) = 4.87.
pH = 14 - 4.87 = 9.13.
Answer:
Question 6
Plants use flowers to absorb photsynthese
Answer:
Light waves carry energy parallel to the motion of the wave, while sound waves carry energy perpendicu
Explanation:
