化學艾維斯
2018-12-2 22:53:13
概念上NH4NO3係完全water soluble
而且佢個實驗係會add excess KOH to consume all NH4NO3
亦即係話all NH4NO3 in fertilizer會溶曬變aq
咁要寫ionic equation時 只約走個K+而唔約走埋個NO3-喺度就變得不太合理
簡單講 溶水拆得開既就應該拆埋
不過往後既年分都有例外
例如我上面講2016 Q6 (c) (ii)
講lemon juice add to NaHCO3
可以接受NaHCO3 + H+ -> Na+ + CO2 + H2O 或HCO3- + H+ -> CO2 + H2O
不過佢係few drops off lemon juice only 即係未必react曬NaHCO3
化學艾維斯
2018-12-5 15:14:07
ideal case要closed system
因為vapor pressure會影響liquid既volatility
不過一般實驗(特別中學)廢事煩 無gas species involve就唔密封
化學艾維斯
2018-12-5 15:14:34
最好啦
最低限度要知過程中Fe既變化
光之賀恩漢
2018-12-5 15:15:20
此回覆已被刪除
化學艾維斯
2018-12-5 15:22:38
yes perfect equilibrium黎講must be closed system(no substances in or out)
但我好懷疑佢會唔會咁問
因為一般中學生做lab d老師為左簡化setup
通常都唔會整到完全closed system
變左大部分學生既認知未必會咁嚴謹
QuitUerr
2018-12-6 13:03:12
Presence of Mobile ion increase rate of corrosion is due to both increase in electrical conductivity of metal and increase in electrical conductivity of water ?
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QuitUerr
2018-12-6 16:28:14
點解 zinc planting 當 coating 未被 damaged 果陣 Zn 係唔會 lose e to Fe?
同樣地點解 tin plant 當 coating 未被 damaged , Fe 唔會 lose e to Ti?