<span>19. Single displacement reactions are always redox reactions (they include reaction between an element and a compound where they will take place of another element in that compound).
20. It should be single displacement, where the displaced ion would form gas.</span>
Answer:
4.74
Explanation:
It is possible to find pH of a buffer (The mixture of a weak acid: Acetic acid, with its conjugate base: Sodium acetate) using Henderson-Hasselbalch equation:
pH = pKa + log₁₀ [A⁻] / [HA]
<em>Where pKa is -log Ka of the weak acid, [A⁻] concentration of the conjugate base and [HA] concentration of the weak acid</em>
pKa of acetic acid is -log 1.8x10⁻⁵ = 4.74
The concentration of both, acetic acid and sodium acetate is 0.1M. Replacing in H-H equation:
pH = pKa + log₁₀ [A⁻] / [HA]
pH = 4.74 + log₁₀ [0.1] / [0.1]
pH = 4.74 + log₁₀ 1
<em>pH = 4.74</em>
Theoretical pH is 4.74
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The correct answer is the combination of a metal with another element.
An alloy is a combination of two or more metallic elements to make a stronger material. For instance, there are bronze alloys, brass alloys, and coin alloys.
We can confirm that an alloy is a combination of one metal with another metal because stainless steel is made of an iron and chromium alloy (iron is a metal; chromium is also a metal). Therefore, we can confirm that option C is the best choice.
Alcohols always contain the Hydroxyl functional group (-O H) - (or just hydroxyl group), which is an oxygen atom bound by a covalent (with shared electron pairs) bound to a hydrogen atom.
I think the first one and the third. They make more sense as of why waves overlap.
Hope I helped
