[DSE化學2017]同學準備好DSE CHEM未?

1001 回覆
44 Like 6 Dislike
2017-04-12 14:32:54
question of the year個人覺得係
electrolysis use 1M H2SO4
同埋add NAOH to nitrophenol 個change

後者點解咁講?
正常eqm pos shift since H+ OH- reacts?
2017-04-12 14:33:10
想問我paper 1 overall 6成的話
但Paper 2得40-50% 係咪會拉低我跌落3

真係要睇係好唔好彩 今年個cut off一定低過上年 但去唔去到你個位好難講
2017-04-12 14:33:18
question of the year個人覺得係
electrolysis use 1M H2SO4
同埋add NAOH to nitrophenol 個change


想問轉咗用H2SO4嗰題有change?我見好似3分
2017-04-12 14:34:29
question of the year個人覺得係
electrolysis use 1M H2SO4
同埋add NAOH to nitrophenol 個change


想問轉咗用H2SO4嗰題有change?我見好似3分

Phenolphthalein 應該係關鍵
2017-04-12 14:34:35
question of the year個人覺得係
electrolysis use 1M H2SO4
同埋add NAOH to nitrophenol 個change

後者點解咁講?
正常eqm pos shift since H+ OH- reacts?


我答會pale咗再深返色
2017-04-12 14:34:41
question of the year個人覺得係
electrolysis use 1M H2SO4
同埋add NAOH to nitrophenol 個change

後者點解咁講?
正常eqm pos shift since H+ OH- reacts?

唔係咁簡單
你wiki pH indicator
有條叫pH = pKa + log [A-]/[HA]既equation (以前AL會學)
係講indicator用
2017-04-12 14:36:18
question of the year個人覺得係
electrolysis use 1M H2SO4
同埋add NAOH to nitrophenol 個change

後者點解咁講?
正常eqm pos shift since H+ OH- reacts?

唔係咁簡單
你wiki pH indicator
有條叫pH = pKa + log [A-]/[HA]既equation (以前AL會學)
係講indicator用

但答題內容是否outc ?
2017-04-12 14:37:39
Standard enthalpy change condition 係咩 是但寫佐25度
2017-04-12 14:38:57
Standard enthalpy change condition 係咩 是但寫佐25度

1ATM
25 度/298k
Standard state of element at its most energetically stable form
2017-04-12 14:39:05
但係fe2(so4)3 fe3+個mol唔係要乘2咩
2017-04-12 14:39:39
但係fe2(so4)3 fe3+個mol唔係要乘2咩

咪 1:2 lor
2017-04-12 14:39:40
question of the year個人覺得係
electrolysis use 1M H2SO4
同埋add NAOH to nitrophenol 個change

後者點解咁講?
正常eqm pos shift since H+ OH- reacts?

唔係咁簡單
你wiki pH indicator
有條叫pH = pKa + log [A-]/[HA]既equation (以前AL會學)
係講indicator用

但答題內容是否outc ?

你做既時候有無諗過
既然佢下面果題你知隻野係用黎做indicator
咁一日未用曬水入面d H+ 應該佢都唔會轉色住
2017-04-12 14:39:55
22/36
2017-04-12 14:41:00
但係fe2(so4)3 fe3+個mol唔係要乘2咩

咪 1:2 lor

因為fe3+有2粒 所以我再乘多次2 變咗1:4
2017-04-12 14:41:00
係咪每年4月都會好快流出份卷
好想睇
2017-04-12 14:41:47
question of the year個人覺得係
electrolysis use 1M H2SO4
同埋add NAOH to nitrophenol 個change

後者點解咁講?
正常eqm pos shift since H+ OH- reacts?

唔係咁簡單
你wiki pH indicator
有條叫pH = pKa + log [A-]/[HA]既equation (以前AL會學)
係講indicator用

但答題內容是否outc ?

你做既時候有無諗過
既然佢下面果題你知隻野係用黎做indicator
咁一日未用曬水入面d H+ 應該佢都唔會轉色住

但如果加NaOH
明顯會令到杯水既[H+] <<<< [OH-] after equilibrium position shift

而[H+] 同時有關個個A- equilibrium 事

問題在?
2017-04-12 14:43:24
Standard enthalpy change condition 係咩 是但寫佐25度

1 atm

25 c

如果係溶液就1 M

寫是但一個有無分
2017-04-12 14:43:51
仆街mc得個23題求4
2017-04-12 14:43:57
有英文版mc卷
要嘅話請留tg 唔會po上嚟費事比HKEAA告
2017-04-12 14:44:27
Standard enthalpy change condition 係咩 是但寫佐25度

1 atm

25 c

如果係溶液就1 M

寫是但一個有無分

點知....
2017-04-12 14:46:54
Standard enthalpy change condition 係咩 是但寫佐25度

1 atm

25 c

如果係溶液就1 M

寫是但一個有無分

點知....

standard condition咪得
2017-04-12 14:49:33
question of the year個人覺得係
electrolysis use 1M H2SO4
同埋add NAOH to nitrophenol 個change

後者點解咁講?
正常eqm pos shift since H+ OH- reacts?

唔係咁簡單
你wiki pH indicator
有條叫pH = pKa + log [A-]/[HA]既equation (以前AL會學)
係講indicator用

但答題內容是否outc ?

你做既時候有無諗過
既然佢下面果題你知隻野係用黎做indicator
咁一日未用曬水入面d H+ 應該佢都唔會轉色住

但如果加NaOH
明顯會令到杯水既[H+] <<<< [OH-] after equilibrium position shift

而[H+] 同時有關個個A- equilibrium 事

問題在?

問題在你上面自己計左HA:A- = 50000:1
亦即係話個eqm本身係極度LHS
所以題目話慢慢加NaOH入去時 係應該會睇唔到轉色
除非你加超多OH 多到push個reaction 個[A-]大返先會睇到黃
2017-04-12 14:50:47
Standard enthalpy change condition 係咩 是但寫佐25度

1 atm

25 c

如果係溶液就1 M

寫是但一個有無分

點知....

standard condition咪得

唔否認岩
但直送隊呢個答案好似risky
2017-04-12 14:52:21
question of the year個人覺得係
electrolysis use 1M H2SO4
同埋add NAOH to nitrophenol 個change

後者點解咁講?
正常eqm pos shift since H+ OH- reacts?

唔係咁簡單
你wiki pH indicator
有條叫pH = pKa + log [A-]/[HA]既equation (以前AL會學)
係講indicator用

但答題內容是否outc ?

你做既時候有無諗過
既然佢下面果題你知隻野係用黎做indicator
咁一日未用曬水入面d H+ 應該佢都唔會轉色住

但如果加NaOH
明顯會令到杯水既[H+] <<<< [OH-] after equilibrium position shift

而[H+] 同時有關個個A- equilibrium 事

問題在?

問題在你上面自己計左HA:A- = 50000:1
亦即係話個eqm本身係極度LHS
所以題目話慢慢加NaOH入去時 係應該會睇唔到轉色
除非你加超多OH 多到push個reaction 個[A-]大返先會睇到黃

Oic 🙏🏿
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