化学のみ：酸を識別し、炭酸塩の観察点を説明する
導入済み| English | 意味 |
|---|---|
| carboxylic acid/ˌkɑːbəkˈsɪlɪk ˈæsɪd/ | カルボン酸 |
| carboxyl group/ˈkɑːbəksɪl ɡruːp/ | カルボキシル基 |
What would explain this observation?
- Ethanoic acid contains both C=O and O–H within one COOH group. Treating its OH as an ordinary alcohol group would predict the wrong family and reactions.
- Start with a prediction. State the quantities or features you would compare, then decide what evidence could distinguish two explanations.
Build the model
- Carboxylic acids 羧酸 contain the –COOH functional group. The first four named members are methanoic acid HCOOH, ethanoic acid CH₃COOH, propanoic acid CH₃CH₂COOH and butanoic acid CH₃CH₂CH₂COOH. The carbon in COOH counts as part of the total carbon number. It has a double bond to one oxygen and a single bond to an O–H group. The individual displayed panels show every atom and bond.
- carboxylic acid: An organic acid containing the –COOH functional group; carboxyl group 羧基: The –COOH group containing C=O and O–H attached to the same carbon.
CH₃CH₂COOH を命名する際に、どの炭素をカウントすべきか？
難易度 1/5 · 100 コイン + 今日初回完了時に小ボーナス付与
COOH内の炭素は鎖に含まれます：CH3CH2COOHは炭素が3つありプロパン酸です。これ無視すると、2つの炭素を持つ名称であるエタン酸という、誤った分子の名前になります。
各専門用語を正確な意味と対応させよ。
難易度 2/5 · 140 コイン + 今日初回完了時に小ボーナス付与
関連する物理量やプロセスを区別するために定義を使用せよ。
Choose evidence that can test it
- These first-four acids dissolve in water to make acidic solutions. A suitable indicator or measured pH demonstrates acidity under the stated conditions. They react with carbonates to form a salt, carbon dioxide and water. For example, ethanoic acid with sodium carbonate forms sodium ethanoate plus the gas and water. Carbon dioxide can turn limewater milky in an approved product test. Reaction with alcohols forms an ester and water, developed in the separate ester lesson.
- Compare a supplied acid structure with the named member by counting all carbons, including COOH. For an approved supervised carbonate comparison, use teacher-selected dilute acids, comparable volumes and carbonate quantities, and record effervescence or gas measurements. Keep a path for gas to escape or reach the approved collector. Indicator colour identifies acidity, not the precise acid; different concentration or temperature can affect reaction rate.
この場合、調査やモデルをより妥当にする2つの習慣は何か。
難易度 2/5 · 140 コイン + 今日初回完了時に小ボーナス付与
条件や仮定を明記することで他者が正確に再現でき、根拠となる証拠を記録することで結論を検証できます。相反する結果を隠すと、誤った結論を疑う証拠を失いますし、単一の測定でより広い主張を成立させることはできません。
Work from known quantities
- State the known values and their units. Choose the relation because its assumptions fit this case, then rearrange before substitution.
- Known: CH₃CH₂COOH has three C, six H and two O atoms, eleven altogether. The acid name is propanoic acid: the two-carbon CH₃CH₂ fragment is joined to a third carbon in COOH. Four represented molecules contain 4×11=44 atoms and eight oxygen atoms. Counting only CH₃CH₂ would give the wrong family member.
Two represented butanoic acid molecules each have formula C₄H₈O₂. Find their total oxygen atoms. Use the same sequence: known quantities → model → relation → substitution → unit and interpretation.
表された2つのブタン酸分子それぞれに分子式 C₄H₈O₂ が存在する。それらの総酸素原子数を求めよ。
難易度 2/5 · 140 コイン + 今日初回完了時に小ボーナス付与
結果は 4 個の原子です。既知：各ブタン酸分子 C4H8O2 は 2 個の酸素原子を含みます。2つの分子の場合：2 × 2 = 4 個の酸素原子が合計で存在します。
Check the conclusion and its limits
- Do not omit the carboxyl carbon or require a balanced carbonate equation where the specification asks only for a description. Common-tier acidity and reaction observations remain separate from the Higher explanation of partial ionisation. A weak-acid description does not establish low concentration or safe handling, and acidity alone does not prove that an unknown is ethanoic acid.
- Return to the original observation. Explain what the result supports, which conditions it assumes, and one way to test a competing explanation.
The OH within a carboxyl group makes every carboxylic acid an ordinary alcohol. This claim is false: The COOH group as a whole makes a carboxylic ACID; the OH within it behaves completely differently from an alcohol OH, releasing H+ in water. The functional group, not the atom list, decides the chemistry.
Chemistry-only: recognise acids and explain carbonate observations: These first-four acids dissolve in water to make acidic solutions. A suitable indicator or measured pH demonstrates acidity under the stated conditions. They react with carbonates to form a salt, carbon dioxide and water. For example, ethanoic acid with sodium carbonate forms sodium ethanoate plus the gas and water. Carbon dioxide can turn limewater milky in an approved product test. Reaction with alcohols forms an ester and water, developed in the separate ester lesson.
カルボキシル基内のOHにより、すべてのカルボン酸は通常のアルコールとなる。
難易度 1/5 · 100 コイン + 今日初回完了時に小ボーナス付与
COOH基全体としてカルボン酸が形成され、その中のOHはアルコールのOHとは全く異なる挙動を示し、水中でH+を放出します。化学性質を決定するのは原子リストではなく官能基です。
–COOH官能基を含む有機酸：その専門用語を記せ。
難易度 1/5 · 100 コイン + 今日初回完了時に小ボーナス付与
カルボン酸とは、–COOH官能基を含む有機酸のことである。