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What is the point of the up arrow (↑) which shows "gas evolved" or "gas liberated", if you could just write the state symbol (g)? And would you write the up arrows (↑) and down arrows (↓) if the state symbols are already included?

Buck Thorn
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JChips
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    They are pretty redundant, imo. – orthocresol Sep 24 '22 at 08:10
  • Probably these arrows should've been included in Arrows used in chemical reactions. – andselisk Sep 24 '22 at 09:13
  • You can use one or the other. If you use the arrow, you don't need to write the state and vice versa. – Nilay Ghosh Sep 24 '22 at 09:33
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    @NilayGhosh Arrows should not be used at all to denote states of aggregation, it's an obsolete and non-standardized notation. – andselisk Sep 24 '22 at 09:54
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    Sometimes, the up arrow is used to imply that the product is removed in the gas state, so the reaction never reaches equilibrium. If you just write (g), it might mean a closed system. However, I don't think there is consensus for interpreting it this way. For solids, you would not distinguish removing the solid from it just sitting there because continuous removal would be difficult to implement. – Karsten Sep 24 '22 at 17:49
  • @Karsten Interesting, I have never noticed the open/closed system interpretation. – Poutnik Sep 25 '22 at 06:07

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