Please help me to answer the following questions in English.
The best answer is going to obtain 10 points, thx !
1. Name an acid which is
( a ) found in our stomach
( b ) found in citrus fruits ( e.g. grapefruit )
( c ) a gas when pure
( d ) dibasic.
2. An acid A with formula CH3COOH is the actice ingredient
in commerical vinegar.
( a ) Suggest a name for the acid A.
( b ) State the basicity of acid A.
( c ) (i) State four obsercable changes when a magnesium
ribbon reacts with an aqueous solution of acid A.
(ii) Write a chemical equation for the reaction of magnesium
and dilute aqueous solution of acid A..
( d ) A dilute aqueous solution of acid A is allowed to react with
sodium carbonate solutio, and effervescence occurs.
(i) Explain why there is effervescence.
(ii) Write an equation for the reaction of acid A and sodium
carbonate in aqueous solution.
F4 chemistry acid and alkalis
2012-02-23 8:24 am
回答 (3)
2012-02-23 8:56 am
✔ 最佳答案
1.(a)
hydrochloric acid
(b)
citric acid
(c)
hydrochloric acid (named as hydrogen chloride when pure)
(d)
sulphuric acid
=====
2.
(a)
ethanoic acid
(b)
monobasic
(c) (i)
Colourless bubbles are formed.
(c) (ii)
Mg(s) + 2CH3COOH(aq) → (CH3COO)2Mg(aq)+ H2(g)
(d) (i)
This is because colourless bubbles of carbon dioxide gas are formed.
(d) (ii)
2CH3COOH(aq) + Na2CO3(aq) → 2CH3COONa(aq)+ H2O(l) + CO2(g)
2012-02-23 22:37:11 補充：
我中學的學習，是由參考別人的答案中找尋進步。同樣一個答案，像我的人會從他人答案中學習，而自我毁滅的人只會抄襲。無論怎樣做，龍還是龍，蟲還是蟲，做法不會改變。最要緊的是，我不是一個教書的材料，要引導他人學習比直接答案難上十倍以上。
參考: andrew
2012-02-24 7:44 am
actually, teaching is not really difficult
you just have to explain the steps
i.e. the logic behind
In your eye, the steps might be just common-sense things
but if you give one or two sentence to explain
it will be a great guidance to the ones that want study from answers, certainly.
2012-02-23 23:44:43 補充：
In most cases, I believe, people have the model answers but they cannot understand the process for working out the answers.
In such cases, an explanation will be a help manifest the solution to them.
you just have to explain the steps
i.e. the logic behind
In your eye, the steps might be just common-sense things
but if you give one or two sentence to explain
it will be a great guidance to the ones that want study from answers, certainly.
2012-02-23 23:44:43 補充：
In most cases, I believe, people have the model answers but they cannot understand the process for working out the answers.
In such cases, an explanation will be a help manifest the solution to them.
2012-02-23 2:54 pm
do the homework by yourself.
if you don't understand what does textbook talk about, you can ask; but not ask someone else to do it for you.
2012-02-23 06:54:49 補充：
Andrew, may I ask for your kind assist to avoid such "helping" by directly giving the answers next time? Your efforts in helping them to develop correct attitude will be much appreciated.
if you don't understand what does textbook talk about, you can ask; but not ask someone else to do it for you.
2012-02-23 06:54:49 補充：
Andrew, may I ask for your kind assist to avoid such "helping" by directly giving the answers next time? Your efforts in helping them to develop correct attitude will be much appreciated.
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