(with) the formula H2O

qizi

Senior Member
Chinese
Chemically there is no difference between the gas, the liquid, and the solid, all of which are made up of molecules with the formula H2O.
Why "with" is used here? I find an example in Longman: Sugar is represented by the simple formula CHO. So could I change it to "by" or any other preposition?
Thank you.
 
  • Loob

    Senior Member
    English UK
    Chemically there is no difference between the gas, the liquid, and the solid, all of which are made up of molecules with the formula H2O.
    I wouldn't change "with" to "by" myself, qizi. "Molecules with the formula H20" means "molecules which have the formula H20".

    In your other sentence, the "by" is related to the passive "is represented".
     

    Moonbug

    New Member
    English (UK)
    "made up of molecules by the formula H20" changes the sense of the statement to mean (nonsensically) that the formula is responsible for making the water out of the molecules. Correct use of "by" would be "made up of molecules represented by the formula H20", following the Longman example. "Represented with" would also be acceptable.
     

    Uncle Bob

    Senior Member
    British English
    I find an example in Longman: Sugar is represented by the simple formula CHO.
    Sorry, I couldn't resist.
    "Longman" may know a lot about language but its chemistry could be better: a sugar is represented by the simple formula (CH2O)6, where all the numbers are subscripts. Also, what is commonly called 'sugar' (= sucrose) has a different formula (C12H22O11), again with numbers as subscripts.
     
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