1) Chemical reaction: HCN + H₂O → CN⁻ + H₃O⁺.
c(HCN) = 2,2 M = 2,2 mol/L.
pKa(HCN) = 9,21.
Ka = 6,16·10⁻¹⁰.
[CN⁻] = [H₃O⁺] = x.
[HCN<span>] = 2,2 M - x.
</span>Ka = [CN⁻] · [H₃O⁺] / [HCN].
6,16·10⁻¹⁰ = x² / 2,2 M -x.
Solve quadratic equation: [CN⁻] = [H₃O⁺] = 0,0000346 M.
[HCN] = 2,2 M - 0,0000346 M = 2,199 M.
2) pH = - log[H₃O⁺].
pH = -log( 0,0000346 M).
pH = 4,46.
Hydrocyanic acid and hydronium ion (H₃O⁺) are acids. Cyanide anion (CN⁻) is the strongest base in the system, cyanide anion accept protons in chemical reaction.
pKb = pKw - pKa.
pKb = 14 - 9,21 = 4,79.
Answer:
Elements, in turn, are pure substances—such as nickel, hydrogen, and helium—that make up all kinds of matter.
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RNA polymerase - synthesises RNA nucleotides from a DNA template to create mRNA
The correct answer is - A- Amount of nitrogen in fertilizer.
The independent variable, in mathematical terms, is the variable whose variation is not dependent on the variations of the another variables.
In this case, the independent variable will be the amount of nitrogen in the fertilizer, as it is not dependent on any other variable. Also, apart from not being dependent on other variables, it is a variable on which the other variables are dependent, which in this case will be the amount of leaves and the amount of blossoms on the tomato plant.