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Re: [Czechlist] Aargh, chemistry!

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  • Tony Long
    Perfect. Couldn t have said it better meself, so I didn t. Tony Whose first-ever real job was mixing krtek-perfect solutions for unappreciative M.Sc. students.
    Message 1 of 13 , Jul 1, 2001
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      Perfect. Couldn't have said it better meself, so I didn't.

      Tony
      Whose first-ever real job was mixing krtek-perfect solutions for unappreciative M.Sc. students.
      Aargh, chemistry!


      Dear Simon,
      do not use "yield" in this context, "yield" is used in chemistry in the
      following context : "yield of a chemical reaction = vytezek chemicke reakce"
      (see also the comment from Karel). In your context, it's better to use
      "amount", although "quantity" is basically correct but see further.
      According to the SNTL Czech-English Chemical Dictionary: mnozstvi = amount,
      quantity, e.g. adsorbed amount, total amount, overall amount, indicator
      amount, trace amount (stopove mnozstvi). "Quantity" is used for "velicina"
      both in chemistry and physics or in technological disciplines : A quantity
      is a technical term for things that can be measured, such as length, mass
      and time. For example, when translating "Fyzikalni veliciny, ktere
      charakterisuji stav systemu...", you should say "Physical quantities that
      characterize the state of a system..." and the term "quantity" is the only
      one you can use here.
      I would not use "fraction" for "mnozstvi" because "fraction" means "podil",
      e.g. in chemistry is frequently used in the context "destilacni podil" in
      the sense "part of something". However, it's tempting to use the term
      "fraction" in your context because of this unhappy "unit" mg/g.
      Nevertheless, I would translate your sentence as "The amount of components
      is given in mass units in mg/g of the tested sample", if it means that the
      amount of components was given in mg (miligrams) and related to the amount
      of the tested sample in g (grams).


      D.P.
      Previous message:

      Simon the Chemist wrote:

      I would welcome your informed opinions on how to translate "mnozstvi"
      in the following context:

      "Mnozstvi komponent jsou uvadena v hmotnostni jednotkach v mg/g
      zkouseneho vzorku."

      It sounds like "yields" to me. Can anyone confirm or correct this?





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    • padamek@mbox.dkm.cz
      Docela by mne zajimalo, jestli se v anglictine ujalo vedecky spravnejsi mass , nebo jestli chemici dodnes pouzivaji beznejsi weight . Byl jsem zvykly
      Message 2 of 13 , Jul 1, 2001
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        Docela by mne zajimalo, jestli se v anglictine ujalo vedecky
        spravnejsi "mass", nebo jestli chemici dodnes pouzivaji
        beznejsi "weight". Byl jsem zvykly prekladat "hmotnost" jako "weight"
        (napriklad "wt.%") ale trebas je to uz dnes zastarale. (Rachel to asi
        bude vedet.)
        S pozdravem Petr
        --- In Czechlist@y..., "Dusan Papousek" <Papousek@m...> wrote:
        > > Nevertheless, I would translate your sentence as "The amount of
        components
        > is given in mass units in mg/g of the tested sample",
      • Simon Vollam
        Morning List, Thanks for all your helpful comments and suggestions. It turns out - as I expected - that the author was referring to the mass of a particular
        Message 3 of 13 , Jul 2, 2001
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          Morning List,

          Thanks for all your helpful comments and suggestions.

          It turns out - as I expected - that the author was referring to the
          mass of a particular gas produced by burning a known amount of
          material (for example, mg of HCN per g of polyurethane foam). This is
          commonly referred to in combustion science as the yield. I agree that
          it is not a yield in the normal chemistry context, i.e. the amount of
          a substance actually produced in a chemical reaction relative to the
          amount predicted theoretically from the reaction stoichiometry. But
          it's a similar concept.

          The author tells me that he wished to stress the fact that it was a
          mass of gas, and not the volume concentration in air. However, I
          wonder whether "vytezek" has a narrower scientific meaning in Czech
          than "yield" does in English. BTW I agree that "amount" is more
          appropriate than "quantity" in this context.

          To answer the mass-vs-weight query, I was always taught that,
          strictly speaking, mass is measured in grammes whereas weight (being
          a force) is measured in Newtons. A man on the moon, for example,
          weighs much less than on earth, but his mass is the same regardless
          of location (relativistic considerations aside).

          On the other hand, strictly speaking one should say "ethanol", not
          "ethyl alcohol", but who cares? Not many chemists do their
          experiments extraterrestrially, and one often sees "weight" used in
          scientific papers as a synonym for mass, especially outside physics.

          Enough, enough. I'm an economist now.

          Thanks again,

          Simon
        • Rachel Thompson
          ... Hi Petr, In normal speech, weight is still the commoner way of expressing what is more correctly termed mass. But I ve never used it as an equivalent for
          Message 4 of 13 , Jul 2, 2001
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            > Docela by mne zajimalo, jestli se v anglictine ujalo vedecky
            > spravnejsi "mass", nebo jestli chemici dodnes pouzivaji
            > beznejsi "weight". Byl jsem zvykly prekladat "hmotnost" jako "weight"
            > (napriklad "wt.%") ale trebas je to uz dnes zastarale. (Rachel to asi
            > bude vedet.)

            Hi Petr,

            In normal speech, weight is still the commoner way of expressing what is
            more correctly termed mass. But I've never used it as an equivalent for
            mass in a chemical text. Until now, I'd have said that that usage was
            out of date, but checking for "weight percent" on Google does bring up
            14,000 hits, so I guess it is still used (perhaps especially in
            America). We always used percentage mass in Britain.

            Rachel
          • Simon Vollam
            ... We always used percentage mass in Britain. I m not sure we always did. Things are much more standardised now, though. Simon
            Message 5 of 13 , Jul 2, 2001
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              --- In Czechlist@y..., "Rachel Thompson" <rachel.thompson@s...> wrote:
              We always used percentage mass in Britain.



              I'm not sure we always did. Things are much more standardised now,
              though.

              Simon
            • Rachel Thompson
              ... Then I suppose it must be a very recent standardisation -- you re not that much older than me, are you? By the time we started doing percentage mass
              Message 6 of 13 , Jul 2, 2001
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                > I'm not sure we always did. Things are much more standardised now,
                > though.

                Then I suppose it must be a very recent standardisation -- you're not
                that much older than me, are you? By the time we started doing
                percentage mass calculations at A-level, everything was "mass" in all
                the course literature, and I'd never heard of this "weight percent"
                until I looked it up this morning.

                But to Petr and others who are wondering what to use, I'd suggest that
                mass is probably the safer bet, since it is more strictly correct.
                Would you go along with that?

                Rachel
              • Simon Vollam
                ... not ... No, only a couple of months older, I would estimate. Seriously, though, I think the SI/IUPAC standardisation efforts have only recently begun to
                Message 7 of 13 , Jul 2, 2001
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                  --- In Czechlist@y..., "Rachel Thompson" <rachel.thompson@s...> wrote:
                  > > I'm not sure we always did. Things are much more standardised now,
                  > > though.
                  >
                  > Then I suppose it must be a very recent standardisation -- you're
                  not
                  > that much older than me, are you?

                  No, only a couple of months older, I would estimate. Seriously,
                  though, I think the SI/IUPAC standardisation efforts have only
                  recently begun to bite. When I was studying chemistry in the late
                  1980s, many of the older professors got decided uppity when we
                  corrected their "antiquated" terminology.

                  Just out of interest,were you taught to use "molecular mass" or
                  "molecular weight"?

                  > But to Petr and others who are wondering what to use, I'd suggest
                  that
                  > mass is probably the safer bet, since it is more strictly correct.
                  > Would you go along with that?

                  Yes indeed, as a rule of thumb. But don't be too surprised if some
                  grey-haired chemist tries to correct you!

                  Simon
                • Rachel Thompson
                  ... Mass. We had some confusion between molar mass and molecular mass , but it was always mass, not weight. Rachel
                  Message 8 of 13 , Jul 2, 2001
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                    > Just out of interest,were you taught to use "molecular mass" or
                    > "molecular weight"?

                    Mass. We had some confusion between "molar mass" and "molecular mass",
                    but it was always mass, not weight.

                    Rachel
                  • Simon Vollam
                    ... mass , ... Interesting. Molecular mass sounds quite alien to me, although I ve nothing against it. It seems those few short months between us have seen
                    Message 9 of 13 , Jul 2, 2001
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                      --- In Czechlist@y..., "Rachel Thompson" <rachel.thompson@s...> wrote:
                      > > Just out of interest,were you taught to use "molecular mass" or
                      > > "molecular weight"?
                      >
                      > Mass. We had some confusion between "molar mass" and "molecular
                      mass",
                      > but it was always mass, not weight.
                      >
                      > Rachel

                      Interesting. Molecular mass sounds quite alien to me, although I've
                      nothing against it. It seems those few short months between us have
                      seen significant changes.

                      I suggest that anyone wishing to find out the currently approved
                      nomenclature visit the IUPAC site
                      http://www.iupac.org/reports/1993/homann/index.html

                      BTW this gives both molecular mass and molecular weight (mind you, it
                      was last updated in 1993 - what have they been doing since then?)

                      Simon, enjoying this trip down (failing-)memory lane
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