有2條唔識做
本帖最後由 雲影軒 於 25-1-2010 15:08 編輯上堂果時呀sir有教點做,但係跟唔切.......題目中英文版都有
1.把200g含有銀的樣本加入100cm^3的2M硝酸(過量)。10cm^3該溶液需用10.7cm^3的0.1M氫氧化鉀進行完全中和。
計算：(i)銀在樣本中的質量百分比
(ii)樣本和稀硝酸反應中所生成的氣態生成物的體積
*相對原子質量：Ag = 107.9
200g of sample containing silver was added to 100cm^3 of 2M nitric acid(excess).10cm^3 of the resulting solution requires 10.7cm^3 of 0.1M potassium hydroxide for complete neutralization.
Calculate：(i)the percentage by mass of silver in the sample
(ii)the volume of the gaseous product formed in the reaction between the sample and the dilute nitric acid
*Relative atomic mass：Ag = 107.9
2.把10g的樣本(含有鐵、碳和雜質)加入過量的濃硫酸，然後加熱，可獲得25.935dm^3的氣態生成物。把10g該樣本加入過量的稀硫酸，可獲得1.29dm^3的氣態生成物。假設樣本中的雜質不會與濃硫酸和稀硫酸反應，計算碳在該樣本中的質量百分比。
*相對原子質量：C = 12.0 ; Fe = 55.8
在常溫常壓下，氣體的摩爾體積 = 24.0dm^3
10g of sample(contains iron,carbon and impurities) was added to excess concentrated sulphuric acid with heating.25.935 dm^3 gaseous products were obtained.When the same mass of sample was added to excess dilute sulphuric acid,1.29 dm^3 of the gaseous product was obtained.Assuming that the impurities neither react with concentrated or dilute sulphuric acid,calculate the percentage by mass of carbon in the sample.
*Relative atomic masses：C = 12.0 ; Fe = 55.8
Molar volume of gas at room temperature and pressure = 24.0dm^3
希望有師兄可以比倒詳細Solution
答案：
1. (i)30.63%
(ii)4.54dm^3
2. 40% 本帖最後由 yukating 於 28-1-2010 19:43 編輯
我可能計錯 - -最後果題個數差少少..
我第二條計錯,我無扣去雜質個質量, - -但我又計吾到... 我可能計錯 - -最後果題個數差少少..
yukating 發表於 25-1-2010 20:05 http://www.nakuz.com/bbs/images/common/back.gif
唔該哂你,步驟真係好詳細......第2題我會自己再計下
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