[2022DSE CHEM化學］問答討論區

Soluble
出magnesium hydroxide

師兄最多都喺失3分啫

MgO soluble in water 嘅咩

唔係唔嘛又一分

very slightly soluble and form Mg(OH)2
跟住再解釋Mg(OH)2 properties

屌
又冇左1分

啱啱拎返份notes 出嚟
又一分
會唔會冇5**

P1+P2 total扣不多於12分應該穩5** (~92%)

感覺今年P2都幾關鍵
好多學生都以為考新題型就驚左
但其實都只係轉個format考返同一個concept

近三屆開始改變出卷模式
簡化左d作答流程 多左d填格仔 graph補線之類
Kc果d唔洗點用既有format畫table去solve
題目就鍾意出一大埋野 個實驗好肉好複雜 但下面d問題出到勁皮毛

題目就鍾意出一大堆野 個實驗好似好複雜 但下面d問題出到勁皮毛

好同意
感覺依家啲題目係想考得廣而唔係考得深

啲實驗出得複雜又係可能純粹嚇下啲考生
做題目完全唔洗用到深嘅概念

tin-plating同galvanizing果題essay有邊5個point要寫？

真 完全唔知為乜
不過可能佢就係想啲考生自己識得filter走啲無用嘅資訊都未定
呢個係我可以唯一作出嘅解釋

你覺得今年5**會唔會落番90/91%？

Similarities:
Tin-plating involves plating of tin onto iron while galvanizing involves plating of zinc onto iron. Both method prevent rusting of iron by preventing exposure of iron to oxygen and water.

Differences:
Tin-plating involve plating of tin onto iron, which is a metal that less reactive than iron. When the plating is scratched, the iron will rust and even rust more readily as it loses electron more readily than tin.

However, galvanizing involve plating of zinc onto iron, which is a metal more reactive than iron. Even though the plating is scratched, the iron will not rust as the zinc loses electrons more readily than iron.

我嘅suugested answer
未必全中 不過我諗都係大概呢啲嘢 唔洗exact wording

應該會
感覺同2019會差不多

同你一樣

使唔使笞 sacrificed protection

anchem最後果條我咁講：
The mole of W in solution T = The mole of Fe2+ in T , so the conc of Fe2+ in sample solution = conc of W in solution T x 100

咁樣得唔得