化学のみ：反復単位を描く際は側基を残すこと
導入済み| English | 意味 |
|---|---|
| side group/saɪd ɡruːp/ | 側鎖基 |
| repeating unit/rɪˈpiːtɪŋ ˈjuːnɪt/ | 反復単位 |
What would explain this observation?
- Propene has three carbon atoms, but only two belong to C=C. In poly(propene), those two form the repeating backbone while the third stays as a CH₃ side group 侧基.
- Start with a prediction. State the quantities or features you would compare, then decide what evidence could distinguish two explanations.
Build the model
- Propene can be written CH₂=CH–CH₃. Addition polymerisation gives the repeating unit 重复单元 –CH₂–CH(CH₃)–. The double-bond carbons become neighbouring backbone carbons with single continuation bonds. The methyl side group remains attached to the same carbon; it is not cut off or automatically inserted as a third backbone position. Each repeating unit retains C₃H₆, the same atoms as the monomer, because no small-molecule by-product is formed.
- repeating unit: The smallest stated structural pattern repeated along the polymer chain; side group: An atom or group attached to the stated polymer backbone rather than continuing that backbone.
プロペンがポリ(プロペン)になる際、CH₃基はどのように変化するか？
難易度 1/5 · 100 コイン + 今日初回完了時に小ボーナス付与
重合ではC=Cのみが開き、CH3 は骨格炭素上の側基として同行します。これによりポリプロピレンは交互するメチルパターンを与えられます。付加反応ではメタンや水は失われません。
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
- Trace the two C=C carbons first and label their attached atoms or groups before changing any bond. In the repeat, the CH₂ carbon bonds to two hydrogens and two backbone neighbours. The CH carbon bonds to one hydrogen, the CH₃ group and two backbone neighbours. Both have four bonds. A supplied CH₂=CHCl example similarly gives –CH₂–CHCl–: chlorine stays attached. This supplied structure is for transferring the model, not an extra list of commercial names to memorise.
- Draw a given alkene in a fixed orientation, circle the double-bond carbons and copy their side groups into the repeating unit. Replace the double bond with a single one, add continuation bonds and brackets, then check every atom and valency. For a reversed task, remove the continuation bonds and restore C=C between the corresponding backbone carbons. Equivalent reversed drawings describe the same connectivity; placement on the page is not a different polymer identity.
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: twelve propene-derived repeating units contain 12×3=36 carbon atoms in total. Twenty-four are backbone carbon atoms, while twelve are in methyl side groups. They also contain 12×6=72 hydrogen atoms in the stated units. Distinguishing backbone from total carbon prevents an incorrect claim that the three-carbon monomer must produce a three-carbon linear repeating backbone.
Sixteen propene-derived repeating units contain three carbon atoms each. Count all their carbon atoms. Use the same sequence: known quantities → model → relation → substitution → unit and interpretation.
プロペン由来の反復単位16個があり、各単位には炭素原子3個含まれている。炭素原子の総数を数えよ。
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 48 個の原子です。既知：16 個のプロピレン由来単位があり、それぞれ 3 個の炭素原子を含みます（2 骨格＋1 側基）。合計 = 16 × 3 = 48 個の炭素原子 – 32 骨格とメチル側基の 16 です。
Check the conclusion and its limits
- Do not change CH₃ into CH₂ while leaving it attached as a side group, add water as an addition product or keep the original C=C. A polymer drawing does not establish biodegradability, recycling availability or mechanical strength by itself. Those claims require separate property and life-cycle evidence. The monomer-to-repeat representation applies on both tiers.
- Return to the original observation. Explain what the result supports, which conditions it assumes, and one way to test a competing explanation.
Every carbon in an alkene monomer must become part of the polymer backbone. This claim is false: Only the two carbons of the original C=C join the backbone. A monomer's other carbons - propene's CH3 - hang off the chain as side groups; they are not forced into the backbone.
Chemistry-only: keep side groups when drawing a repeating unit: Trace the two C=C carbons first and label their attached atoms or groups before changing any bond. In the repeat, the CH₂ carbon bonds to two hydrogens and two backbone neighbours. The CH carbon bonds to one hydrogen, the CH₃ group and two backbone neighbours. Both have four bonds. A supplied CH₂=CHCl example similarly gives –CH₂–CHCl–: chlorine stays attached. This supplied structure is for transferring the model, not an extra list of commercial names to memorise.
アルケン単量体のすべての炭素原子は、重合体骨格の一部にならなければならない。
難易度 1/5 · 100 コイン + 今日初回完了時に小ボーナス付与
元のC=Cの2つの炭素のみが骨格に結合します。単量体の他の炭素、すなわちプロピレンのCH3 は鎖から側基として突き出ており、骨格に強制されることはありません。
重合体鎖に沿って繰り返される最小の構造パターン：技術用語を記せ。
難易度 1/5 · 100 コイン + 今日初回完了時に小ボーナス付与
繰り返し単位とは、重合体鎖に沿って繰り返される最小の構造パターンを指す。