攪到要再拍過 多謝比面 巴打有冇諗過讀個教育文憑之類去日校教呀？諗就有諗過
Asso pre-lab
Analysis of Vitamin C tablets
1. Explain why should the starch solution be added only when the reaction mixture becomes pale yellow.
2. It is known that Vitamin C decomposes upon to air or heating. Briefly describe how you would investigate these two factors.
Asso pre-lab
Analysis of Vitamin C tablets
1. Explain why should the starch solution be added only when the reaction mixture becomes pale yellow.
2. It is known that Vitamin C decomposes upon to air or heating. Briefly describe how you would investigate these two factors.
1. Because starch irreversibly binds with I2 at high concentration of I2(aq), making some I2 remain adsorbed on the complex and go unreacted, and so the end point is inaccurate.
2. perform the experiment few more times by using Vitamin C tablets that are exposed in air for different time / heat under different temperature.
btw, quantitative analysis of Vitamin C都算係中學level,以前AL pastpaper都好鍾意出
iodine titration 用starch做indicator既注意事項都算common.
Thx
仲有點解加左H2SO4要即刻做titration 唔即刻做會有咩發生
你好巴打
想問增加催化劑表面積會唔會加快反應速率？
你好巴打
想問增加催化劑表面積會唔會加快反應速率？
會
因為可以同一時間有更多反應物粒子附著(adsorption)
會增加催化效能
巴打覺得dse chem需唔需要識計DBE?
AL industrial chem pastpaper有啲ln(concentration) against time嘅圖
dse係咪out syl？
AL industrial chem pastpaper有啲ln(concentration) against time嘅圖
dse係咪out syl？
係 唔會再叫你ln 因為DSE chem唔require到你識d識ln
最多要識到log
AL industrial chem pastpaper有啲ln(concentration) against time嘅圖
dse係咪out syl？
係 唔會再叫你ln 因為DSE chem唔require到你識d識ln
最多要識到log
唔該巴打