Chem CE 2004年 MC 第12,27,28,35題 @ rll33xb99t的部落格

標題:

Chem CE 2004年 MC 第12,27,28,35題

發問:

如上，請問第12題係點計嘅呢? 跟住第27題點解唔係B condensation呢 28唔知點解第2個方法唔得最後，35點解第2個choice唔得呢? 唔該晒~~~ 更新: 都仲係唔係好明27條，點解esterification內，alkanoic acid + alkanol ─conc.H2SO4→ester + H2O 就係condensation reaction. 但係呢個case就係dehydration呢?可唔可以詳細少少呢~~~ 35, foam係咩chemical嚟架? 點解burn 佢會decompose嘅? 更新 2: Q. 27) 即係如果個H2O係由一個compound內抽出來就係dehydration, 而由兩個compounds各自攞少少合成H2O就係condensation啦?

最佳解答:

此文章來自奇摩知識+如有不便請留言告知

12 For 100g of the substance X O no of mole 75.7/74.9 24.3/16 =1.011 =1.51875 simplist mole ratio 1 1.51875/1.011 = 1.5 empirical formula 2 3 27 condensation should be some liquid condense or a small molecule escape in a macromolecule like plastic of course it is not the case here so as h2so4 is dehydrating agent 28 ethene's density is similar to gas it is inappropriate to collect in this method as it is not easy for ethene to displace the air by upward delivery D is correct 35 foam will be decomposed by the burning sodim the sodium will continue to burn vigorously 2006-12-30 23:11:17 補充： Xno of mole 75.7-74.9 =1.01O no. of mole 24.3/16=1.51875simpliest mole ratio X: O = 1: 1.51875/1.01=1:1.5=2:3 2006-12-31 08:56:55 補充： 27因為呢個唔係esterification lor你細心睇佢係一個molecule(一個alkanol)入面冇左一個H20compound而唔係acid冇個h alkanol冇oh而變成H2Oalkanol本身唔會生成H2O而REACTION內只有H2SO4的DEHYDRATING PROPERTIES會生成水所以只有D35因為呢條係out ge(in CE level)我諗係CO2因為al都出過同一樣的野佢話co2會比decompose...oxygen一樣落到去禁宜家得呢個答案唔對....我諗應係co2 2007-01-01 13:28:28 補充：可以禁樣講而特別呢條係dehydration的原因係因為有conc. h2so4...要記住h2so4係一個strong dehydrating agent~

其他解答: