Polyprotic Acid Example Chemistry Problem

Polyprotic Acid Example Chemistry Problem A polyprotic acid is an acid that can donate more than one hydrogen atom (proton) in an aqueous solution. To find the pH of this type of acid, its necessary to know the dissociation constants for each hydrogen atom. This is an example of how to work a polyprotic acid chemistry problem. Polyprotic Acid Chemistry Problem Determine the pH of a 0.10 M solution of H2SO4. Given: Ka2 1.3 x 10-2 Solution H2SO4 has two H (protons), so it is a diprotic acid that undergoes two sequential ionizations in water: First ionization: H2SO4(aq) → H(aq) HSO4-(aq) Second ionization: HSO4-(aq) ⇔ H(aq) SO42-(aq) Note that sulfuric acid is a strong acid, so its first dissociation approaches 100%. This is why the reaction is written using → rather than ⇔. The HSO4-(aq) in the second ionization is a weak acid, so the H is in equilibrium with its conjugate base. Ka2 [H][SO42-]/[HSO4-] Ka2 1.3 x 10-2 Ka2 (0.10 x)(x)/(0.10 - x) Since Ka2 is relatively large, its necessary to use the quadratic formula to solve for x: x2 0.11x - 0.0013 0 x 1.1 x 10-2 M The sum of the first and second ionizations gives the total [H] at equilibrium. 0.10 0.011 0.11 M pH -log[H] 0.96 Learn More Introduction to Polyprotic Acids Strength of Acids and Bases Concentration of Chemical Species First Ionization H2SO4(aq) H+(aq) HSO4-(aq) Initial 0.10 M 0.00 M 0.00 M Change -0.10 M +0.10 M +0.10 M Final 0.00 M 0.10 M 0.10 M Second Ionization HSO42-(aq) H+(aq) SO42-(aq) Initial 0.10 M 0.10 M 0.00 M Change -x M +x M +x M At Equilibrium (0.10 - x) M (0.10 + x) M x M

Treatment of Words That Include Self

Treatment of Words That Include Self Treatment of Words That Include â€Å"Self† Treatment of Words That Include â€Å"Self† By Mark Nichol Appropriately enough, the self-centered word self, when combined with others, sometimes gets special treatment. Self, as a prefix, is attached by a hyphen to other words in several parts of speech. The combination can be a noun (self-control), an adjective (self-absorbed), a verb (self-medicate), or an adverb (self-importantly). It can also refer literally to a person (self-regard) or can figuratively apply to an inanimate object (self-contained). However it is used, though, it is always, with one aberrant exception I’ll refer to below, hyphenated. In adjectival usage, although most phrasal adjectives are hyphenated before a noun but left open after (â€Å"The well-known artist drew a big crowd,† but â€Å"That artist is well known†), compounds that include the prefix self are hyphenated in both positions: â€Å"The self-possessed girl was confident but not conceited,† and â€Å"That girl is remarkably self-possessed.† This rule applies also to all, another prefix used in phrasal adjectives: â€Å"The all-inclusive policy was more successful†; â€Å"The policy is all-inclusive.† Ex, although not employed in phrasal adjectives, is another prefix always hyphenated to the word that follows: â€Å"That’s her ex-boyfriend.† The exception for the prefix self I referred to above is this: Though self-conscious and self-consciously are so constructed, the antonym presents a problem: Words are often strung together into phrases with hyphens (â€Å"She had an annoying devil-may-care attitude†), but this strategy is considered inappropriate when prefixes are concerned. Un-self-consciously looks awkward. Unfortunately, the preferred alternative, unselfconsciously, is equally repugnant. The solution? Instead of writing â€Å"His unselfconsciousness was refreshing,† write â€Å"His lack of self-consciousness was refreshing.† As an alternative to the adverbial form in, for example, â€Å"They played together unselfconsciously,† try â€Å"They played together with no self-conscious behavior.† In all other usage, though, words in which self or its plural form appears when self is followed by a suffix (selfish, selfless) or when it is combined with a pronoun (yourself, myself, itself, ourselves, themselves, and so on) are not hyphenated. Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Expressions category, check our popular posts, or choose a related post below:Grammar Test 1Hang, Hung, Hanged75 Synonyms for â€Å"Hard†