原子、元素、化合物：化学記号を読み取ること
導入済み| English | 意味 |
|---|---|
| compound/ˈkɒmpaʊnd/ | 化合物 |
| element/ˈelɪmənt/ | 元素 |
What would explain this observation?
- O is the symbol for oxygen, while O₂ represents an oxygen molecule. Two atoms joined together do not necessarily make a compound 化合物: their element 元素 identities matter.
- Start with a prediction. State the quantities or features you would compare, then decide what evidence could distinguish two explanations.
Build the model
- An atom is the smallest part of an element that can exist. An element contains one type of atom, defined by proton number. A compound contains two or more elements chemically combined in fixed proportions. Water, H₂O, contains hydrogen and oxygen in a 2:1 atom ratio; oxygen, O₂, is still an element. A chemical reaction forms new substances and often produces a detectable energy change. Separating a compound into its elements requires chemical change.
- element: A substance containing only one type of atom defined by proton number; compound: A substance containing two or more elements chemically combined in fixed proportions.
どの物質が化合物か？
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化合物は、化学的に結合した2つ以上の異なる元素から成る：水素と酸素を含む水のように。O2とヘリウムはそれぞれ1つの元素のみを含んでいるため、粒子数が何であろうと化合物ではない。
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
- Symbols use an uppercase first letter and, where present, a lowercase second letter: Co is cobalt, whereas CO is carbon monoxide. For the first twenty elements learn H hydrogen, He helium, Li lithium, Be beryllium, B boron, C carbon, N nitrogen, O oxygen, F fluorine, Ne neon, Na sodium, Mg magnesium, Al aluminium, Si silicon, P phosphorus, S sulfur, Cl chlorine, Ar argon, K potassium and Ca calcium. Group 1 also includes Rb rubidium, Cs caesium and Fr francium; Group 7 includes F fluorine, Cl chlorine, Br bromine, I iodine and At astatine. Use the supplied periodic table for other specified elements, including Fe iron, Cu copper and Zn zinc. Very radioactive francium and astatine are names to interpret from the table, not school reaction specimens.
- Read a formula by identifying each element symbol before applying its subscript. A subscript applies to the symbol immediately before it, or to an entire bracketed group. Name MgO magnesium oxide, NaCl sodium chloride and Ca(OH)₂ calcium hydroxide. Compare diagrams of separate atoms, molecules of one element and compound particles; keep particle identity distinct from the number of particles.
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: one formula unit of Ca(OH)₂ contains one Ca, two O and two H, five atoms in all. Three formula units contain 3 calcium, 6 oxygen and 6 hydrogen atoms, fifteen total. The coefficient multiplies the entire formula; it does not change the fixed Ca:O:H ratio of 1:2:2.
How many oxygen atoms are represented by four formula units of Ca(OH)₂? Use the same sequence: known quantities → model → relation → substitution → unit and interpretation.
Ca(OH)₂ の式量単位4つに含まれる酸素原子の数を答えよ。
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 8 個の原子である。既知：各 Ca(OH)2 単位には 2 個の酸素原子が含まれる（下付き数字 2 は括弧内の両方の原子に掛け算される）。4つの式単位には 4 × 2 = 8 個の酸素原子がある。係数は式全体を掛け算する。
Check the conclusion and its limits
- A molecule can contain only one element, and some compounds form lattices rather than separate molecules. Heating a mixture to separate it is not automatically a chemical reaction. New substances, rather than an energy change alone, establish chemical change.
- Return to the original observation. Explain what the result supports, which conditions it assumes, and one way to test a competing explanation.
Every particle containing two atoms is a compound. This claim is false: O2 has two atoms but one element, so it is a molecule of an element, not a compound. A compound requires at least two different elements chemically combined.
Atoms, elements and compounds: read the chemical symbols: Symbols use an uppercase first letter and, where present, a lowercase second letter: Co is cobalt, whereas CO is carbon monoxide. For the first twenty elements learn H hydrogen, He helium, Li lithium, Be beryllium, B boron, C carbon, N nitrogen, O oxygen, F fluorine, Ne neon, Na sodium, Mg magnesium, Al aluminium, Si silicon, P phosphorus, S sulfur, Cl chlorine, Ar argon, K potassium and Ca calcium. Group 1 also includes Rb rubidium, Cs caesium and Fr francium; Group 7 includes F fluorine, Cl chlorine, Br bromine, I iodine and At astatine. Use the supplied periodic table for other specified elements, including Fe iron, Cu copper and Zn zinc. Very radioactive francium and astatine are names to interpret from the table, not school reaction specimens.
2個の原子を含むすべての粒子は化合物である。
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O2 は2つの原子を持つが1つの元素のみなので、これは元素の分子であり、化合物ではない。化合物には、化学的に結合した少なくとも2つの異なる元素が必要である。
陽イオン数によって定義される一種類の原子のみからなる物質: 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
元素とは、陽イオン数によって定義される一種類の原子のみからなる物質を指す。