[化学論文のための英語講座] 第86回：化学の日 Chemistry Day
2026年1月26日
(English version is here.)
10月23日は化学の日！「化学の日」の由来になったアボガドロ定数とは何でしょうか？
日本語の記事を英訳しました。英訳のポイントを解説していますので是非ご覧ください。
出典（日本語の記事）：https://www.chemistry.or.jp/news/information/1023-13.html
October 23rd is Chemistry Day! What is the 1)Avogadro Constant that gave rise to Chemistry Day?
As 2)the chemistry of gases developed in the 18th century, it was discovered that when gases react with other gases, the volume ratio of reactants to products is a simple ratio. For example, two volumes of hydrogen react with one volume of oxygen to produce two volumes of water (water vapour). Some chemists tried to explain this by considering gases to be comprised of atoms, but this gave rise to contradictions and did not 3)work. In 1811, Italian chemist Avogadro proposed two hypotheses that 4)could resolve the contradictions.
1. Oxygen, hydrogen, nitrogen 5)and so on, do not exist as atoms, but rather as molecules made up of two atoms.
2. The number of atoms contained in a gas of the same temperature and same volume are the same, regardless of the type of gas.
His idea was not immediately accepted, but about fifty years later (around the time of the Meiji Reformation) Cannizzaro re-introduced the idea and it became accepted by chemists.
Atoms and molecules are extremely small and light, and thus it is impossible to measure their mass 6)one by one, but it is convenient to think of a fixed number of them as a unit. The units one dozen (twelve) or one gross (12 dozen) can be used for large numbers of pencils, but in chemistry atoms and molecules are measured in units of moles. For example, two moles of hydrogen react with one mole of oxygen to give two moles of water. This can be simply expressed as in the chemical formula below. (The coefficient 1 before O2 is omitted.)
2H2 + O2 → 2 H2O (The 1 placed before the O2 has been deleted.)
The number of atoms or molecules in one mole is a 7)colossal 6.023 x 1023. 6 x 1023, expressed in ordinary fashion, is 6 followed by 23 zeros; a 8)gigantic number. The number of particles contained in one mole, whether atoms or molecules, is 6.023 x 1023, so the number per mole is written as 6.023 x 1023mole-1. (6.024 x 1023/mole) This is the Avogadro constant.
Returning to the topic of gases, 1 mol of gas at 0 °C and 1 atmosphere pressure (1013 hectopascals) occupies a volume of 22.4 litres. The number of molecules contained in this gas is 6.02 x 1023.
The number of grams contained in one mole of atoms or molecules is determined by 9)attaching the unit g (gram) to the atomic or molecular weight. The atomic weight of carbon is 12.01. That is to say, 12.01 grams of carbon 10)contain 6.023 x 1023 atoms. The atomic weight of hydrogen is 1.008 and thus, the molecular weight of molecular hydrogen H2 is 2.016. In other words, 2.016 grams of H2 contain 6.023 x 1023 hydrogen molecules.
Currently, Avogadro constant is calculated to be 6.02214076 x 1023 to an accuracy of 9 digits, but chemists are working to find even greater precision.
[解説]
下線1)：アボガドロ定数を英語で言うと「Avogadro Constant」になりますが、英語圏では「Avogadro's Number」をよく使います。どちらを使っても自然ですので原文に近い「Avogadro Constant」を使います。
下線2)：「気体を取り扱う化学」は英語で言うと「chemistry dealing with gases」になりますが、「the chemistry of gases」の方が簡潔で自然です（前者を使っても特に違和感はありません）。「the」は任意です。
下線3)：ここでは「work」にしていますが、代わりに「progress」または「take hold」の方が綺麗だと思います。
下線4)：「could resolve」は過去の意味と仮定の意味を含み、両方が文脈に合いますが原文は過去の意味がありました。原文と若干異なりますが、代わりに「resolved」を使用しても問題ありません。
下線5)：「and so on」、「et cetera」、「etc.」は同じです。
下線6)：「one-by-one」の代わりに「individually」も使えます。
下線7)：「膨大な」はgigantic, enormous, colossalです。
下線8)：「とてつもない」はfantastical, incredible, absurd, extravagantもありますが、ここではgigantic, enormous, colossal が良いと思います。
下線9)：代わりに「fixing」も使えます。
下線10)：代わりに「comprise」も使えます。
次回もどうぞお楽しみに。
October 23rd is Chemistry Day! What is Avogadro's number, the origin of Chemistry Day? We have translated the Japanese article into English. Please take a look as we explain the key points of the English translation.
Source (Japanese article)
https://www.chemistry.or.jp/news/information/1023-13.html
October 23rd is Chemistry Day! What is the 1)Avogadro Constant that gave rise to Chemistry Day?
As 2)the chemistry of gases developed in the 18th century, it was discovered that when gases react with other gases, the volume ratio of reactants to products is a simple ratio. For example, two volumes of hydrogen react with one volume of oxygen to produce two volumes of water (water vapour). Some chemists tried to explain this by considering gases to be comprised of atoms, but this gave rise to contradictions and did not 3)work. In 1811, Italian chemist Avogadro proposed two hypotheses that 4)could resolve the contradictions.
1. Oxygen, hydrogen, nitrogen 5)and so on, do not exist as atoms, but rather as molecules made up of two atoms.
2. The number of atoms contained in a gas of the same temperature and same volume are the same, regardless of the type of gas.
His idea was not immediately accepted, but about fifty years later (around the time of the Meiji Reformation) Cannizzaro re-introduced the idea and it became accepted by chemists.
Atoms and molecules are extremely small and light, and thus it is impossible to measure their mass 6)one by one, but it is convenient to think of a fixed number of them as a unit. The units one dozen (twelve) or one gross (12 dozen) can be used for large numbers of pencils, but in chemistry atoms and molecules are measured in units of moles. For example, two moles of hydrogen react with one mole of oxygen to give two moles of water. This can be simply expressed as in the chemical formula below. (The coefficient 1 before O2 is omitted.)
2H2 + O2 → 2 H2O (The 1 placed before the O2 has been deleted.)
The number of atoms or molecules in one mole is a 7)colossal 6.023 x 1023. 6 x 1023, expressed in ordinary fashion, is 6 followed by 23 zeros; a 8)gigantic number. The number of particles contained in one mole, whether atoms or molecules, is 6.023 x 1023, so the number per mole is written as 6.023 x 1023mole-1. (6.024 x 1023/mole) This is the Avogadro constant.
Returning to the topic of gases, 1 mol of gas at 0 °C and 1 atmosphere pressure (1013 hectopascals) occupies a volume of 22.4 litres. The number of molecules contained in this gas is 6.02 x 1023.
The number of grams contained in one mole of atoms or molecules is determined by 9)attaching the unit g (gram) to the atomic or molecular weight. The atomic weight of carbon is 12.01. That is to say, 12.01 grams of carbon 10)contain 6.023 x 1023 atoms. The atomic weight of hydrogen is 1.008 and thus, the molecular weight of molecular hydrogen H2 is 2.016. In other words, 2.016 grams of H2 contain 6.023 x 1023 hydrogen molecules.
Currently, Avogadro constant is calculated to be 6.02214076 x 1023 to an accuracy of 9 digits, but chemists are working to find even greater precision.
[Explanation]
Underline 1: Direct translation into English gives Avogadro Constant, but in the Anglosphere Avogadro's Number is commonly used. Using either is natural, but the closer to the original text Avogadro's Constant is used here.
Underline 2: Direct translation into English gives chemistry dealing with gases, but the chemistry of gases is concise and more natural (Use of the former is not strange). Using the is optional.
Underline 3: Here work is used, but alternatively progress or take hold would be better, I think.
Underline 4: Could resolve includes past and conditional meanings and both fit the context, however, the original text contains the past meaning. Although slightly different from the original text, alternatively using resolved is not a problem.
Underline 5: And so on, et cetera, and etc. are the same.
Underline 6: Individually can be used instead of one-by-one.
Underline 7: Gigantic, enormous, and colossal work here.
Underline 8: This can be translated as fantastical, incredible, absurd, and extravagant, but gigantic, enormous, and colossal also work here.
Underline 9: Alternatively, fixing can be used.
Underline 10: Alternatively, comprise can be used.
We look forward to seeing you next time.