Re: some questions here to ask you... -- Chemistry

[ Show ]

Support VoyForums

[ Shrink ]

VoyForums Announcement: Programming and providing support for this service has been a labor of love since 1997. We are one of the few services online who values our users' privacy, and have never sold your information. We have even fought hard to defend your privacy in legal cases; however, we've done it with almost no financial support -- paying out of pocket to continue providing the service. Due to the issues imposed on us by advertisers, we also stopped hosting most ads on the forums many years ago. We hope you appreciate our efforts.

Show your support by donating any amount. (Note: We are still technically a for-profit company, so your contribution is not tax-deductible.) PayPal Acct: Feedback:

Donate to VoyForums (PayPal):

[ Login ] [ Contact Forum Admin ] [ Main index ] [ Post a new message ] [ Search | Check update time ]

[ Next Thread | Previous Thread | Next Message | Previous Message ]

Date Posted: 06:38:46 10/31/01 Wed
Author: Mr. Yeo Woei Ter
Subject: Re: some questions here to ask you...
In reply to: Chor Hoon 's message, "some questions here to ask you..." on 04:52:35 10/31/01 Wed

First of all, I'll encouraged all of you to ask questions here, so everyone can learn at the same time.

Regarding Q3 on Topic 7 Pg.7, that question is on Reversible reaction, Chapter 14 of your textbook and is already out of the syllabus. So you can gladly skip (a) and (b) of that question EXCEPT part (c), which is a question on speed of reaction and that is STILL IN YOUR SYLLABUS!

As for your question, it is true that elements in the same Group has similar chemical and physical properties (Pg. 222 of "*textbook!"), but as we go down the group, the reactivity and physical properties of the elements changes.

For example, all Group I elements are soft metals with low melting point; and all of them react with water to form alkaline solution. That's their similarity.

But their densities generally increases down the Group while their melting points decrease down the Group. The Group I elements also become more reactive down the group. This is the trend of Group I elements.

As for your second question, reactive metals are extracted by electrolysing a MOLTEN ionic compound of the metal! (See page 252, Section 11.4, last statement, of "*textbook!")

Yes, if you electrolyse an aqueous solution of sodium chloride for example, then hydrogen ions(from water) will be discharged at the cathode, and hydrogen gas will be produced.

However, if you electrolyse MOLTEN sodium chloride, then the product at the cathode will be different. The molten compound contains only two ions, Na⁺ and Cl^- ions. Na⁺ ions will be attracted to the cathode where it will be discharged:
At the cathode: Na⁺(l) + e^- ---> Na(l)

Chloride ions will be attracted to the anode.
At the anode: Cl^-(l)---> Cl(g) + e^-
Cl(g) + Cl(g) ---> Cl₂(g)

Thus, this electrolysis will yield sodium metal at the cathode and chlorine at the anode.

Hope that answers your question!

[ Next Thread | Previous Thread | Next Message | Previous Message ]