関連する実験動画
Updated: Jul 12, 2026

11:00
Determination of the Gas-phase Acidities of Oligopeptides
Published on: June 24, 2013
まとめ
雨は弱い酸であり,硫酸のような強い酸による酸性の増加という考えに異議を唱える. この発見は,酸性雨と環境化学の理解に影響を与えます.
科学分野:
- 環境化学 環境化学
- 大気科学 大気科学
背景:
- 現存する概念は,雨の酸性の増加を示唆し,これはしばしば硫黄酸のような強い酸に起因する.
- 降雨の真の酸性を理解することは,環境モニタリングに不可欠です.
研究 の 目的:
- 雨サンプルにおける自由水素イオン濃度と総水素イオン濃度を比較する.
- 雨の酸性の増加とその原因に関する主張の妥当性を評価する.
主な方法:
- 雨サンプルを分析して,自由な水素イオン濃度を測定する.
- 雨のサンプルを分析して,水素イオン総濃度を測定する.
- 2つの濃度測定の比較分析.
主要な成果:
- 雨のサンプルには,弱い酸の特徴が一貫して見られます.
- 観察された弱い酸性性質は,強い酸による酸性の有意な増加の概念と矛盾しています.
- 雨の全体的な酸性に対する強い酸の貢献は過大評価されているかもしれない.
結論:
- 雨の固有の弱い酸性性は,酸性の増加に関する広く受け入れられている理論に疑問を投げかけます.
- この発見は,雨の化学的性質を左右する源とメカニズムの再評価を示唆している.
- 大気汚染物質が降水化学に与える影響を正確に評価するためには,さらなる研究が必要である.
関連する概念動画
Precipitation of Ions
Predicting Precipitation
The equation that describes the equilibrium between solid calcium carbonate and its solvated ions is:
The equation that describes the equilibrium between solid calcium carbonate and its solvated ions is:
Precipitation and Co-precipitation
Precipitation and coprecipitation methods can be used to separate a mixture of ions in a solution. In qualitative inorganic analysis, ions that form sparingly soluble precipitates with the same reagent are separated based on the differences in solubility products. For example, consider the separation of Cu(II) and Fe(II) ions by precipitation as insoluble sulfides. First, copper(II) sulfide is precipitated by the addition of acidic H2S, where the dissociation of H2S is suppressed. Adding H2S...
Types of Coprecipitation
Coprecipitation is the contamination of a precipitate by otherwise soluble species and occurs via different processes. In colloidal precipitates, coprecipitation occurs via surface adsorption. For instance, barium sulfate has a primary layer of adsorbed barium ions and a secondary layer of nitrate counterions. This results in contamination of the precipitate by barium nitrate.
Sometimes, ions in a crystal lattice can undergo isomorphous replacement by inclusions of similar charge and size. For...
Sometimes, ions in a crystal lattice can undergo isomorphous replacement by inclusions of similar charge and size. For...
Precipitation Processes
The experimental conditions in a gravimetric analysis should be optimized to maximize the particle size and purity of the obtained precipitate. Ideally, the concentration of the precipitating reagent should be low with effective stirring to maintain low relative supersaturation for the growth of large crystals. In homogeneous precipitation, the precipitant is slowly generated by a chemical reaction in the solution to avoid local reagent excesses. For example, urea decomposes gradually to...
Precipitation Reactions
In a precipitation reaction, aqueous solutions of soluble salts react to give an insoluble ionic compound – the precipitate. The reaction occurs when oppositely charged ions in solution overcome their attraction for water and bind to each other, forming a precipitate that separates out from the solution. Since such reactions involve the exchange of ions between ionic compounds in aqueous solution, they are also referred to as double displacement, double replacement, exchange reactions, or...
Mixtures of Acids
The pH of a solution containing an acid can be determined using its acid dissociation constant and its initial concentration. If a solution contains two different acids, then its pH can be determined using one of several methods depending upon the relative strength of the acids and their dissociation constants.
A Mixture of a Strong Acid and a Weak Acid
In a mixture of a strong acid and a weak acid, the strong acid dissociates completely and becomes a source of almost all the hydronium ions...
A Mixture of a Strong Acid and a Weak Acid
In a mixture of a strong acid and a weak acid, the strong acid dissociates completely and becomes a source of almost all the hydronium ions...

