Gunakan MimeTex/LaTex untuk menulis simbol dan persamaan matematika.

Selamat datang, Pengunjung. Silahkan masuk atau mendaftar. Apakah anda lupa aktivasi email?

Desember 06, 2021, 06:46:24 PM

Masuk dengan nama pengguna, kata sandi dan lama sesi

Topik Baru

Artikel Sains

Anggota
Stats
  • Total Tulisan: 139668
  • Total Topik: 10408
  • Online Today: 26
  • Online Ever: 441
  • (Desember 18, 2011, 12:48:51 AM)
Pengguna Online
Users: 0
Guests: 27
Total: 27

Ikuti ForSa

ForSa on FB ForSa on Twitter

Penulis Topik: Raksa (Hg)  (Dibaca 18434 kali)

0 Anggota dan 1 Pengunjung sedang melihat topik ini.

Offline soni sascori

  • Dosen
  • ****
  • Tulisan: 115
  • IQ: 20
  • Gender: Pria
Re: Raksa (Hg)
« Jawab #15 pada: Februari 11, 2009, 08:35:01 AM »
Q pernah pegang logam Hg murni bukan dari termometer pecah tapi Hg yang digunakan para penambang emas dengan metode konvensional (dulang) dan bukan dalam bentuk senyawaannya....! gmana donk???

Hg berbahaya jika ada di dalam tubuhkan?

tangan Q juga gak bengkak seperti tikus diatas....!!!!!!
n_COn

Offline syx

  • Global Moderator
  • Profesor
  • *****
  • Tulisan: 4.540
  • IQ: 341
  • Gender: Pria
    • Kliping Koran
Re: Raksa (Hg)
« Jawab #16 pada: Februari 11, 2009, 09:36:08 AM »
tikus yang gw maksud bengkak bukan karena Hg, tapi karena diberi obat yang bikin bengkak... Hg-nya dipake untuk membantu pengukuran volume hingga pembengkakan dan reduksinya bisa diukur. Hg kan sifat kohesinya lebih besar hingga tidak bakal nempel di kaki tikus yang diukur.

Offline soni sascori

  • Dosen
  • ****
  • Tulisan: 115
  • IQ: 20
  • Gender: Pria
Re: Raksa (Hg)
« Jawab #17 pada: Februari 11, 2009, 09:47:58 AM »
mungkin gak hg bisa masuk dari pori2 kulit?

Offline nandaz

  • Profesor
  • *****
  • Tulisan: 1.849
  • IQ: 75
  • Gender: Pria
  • ...Mad about Sci_mistery
Re: Raksa (Hg)
« Jawab #18 pada: Februari 11, 2009, 11:51:58 AM »
...menurutku...sih, raksa akan melepuhkan kulitmu dahulu dan lewat celah itu raksa baru akan masuk kedalam tubuh...tentu dalam konsentrasi tinggi...begitukah Mr.syx...?
starting by doing what is necessary, then what is possible and suddenly you are doing the impossible...
\dia\cal{ANONYMOUS}\cl

Offline syx

  • Global Moderator
  • Profesor
  • *****
  • Tulisan: 4.540
  • IQ: 341
  • Gender: Pria
    • Kliping Koran
Re: Raksa (Hg)
« Jawab #19 pada: Februari 11, 2009, 11:42:35 PM »
penyerapan Hg ga terlalu bagus melalui kulit yang sehat, kecuali dalam kondisi luka terbuka atau dalam sediaan kosmetik yang mengandung enhancher. paparan biasanya melalui pernapasan dan makanan.

Use of mercury compounds in cosmetics including use as skinbleaching agents in cosmetic preparations also regarded as drugs.

(a) Mercury-containing cosmetic preparations have been represented for many years as skin-bleaching agents or as preparations to remove or prevent freckles and/or brown spots (so-called age spots). Preparations intended for such use are regarded as drugs as well as cosmetics. In addition to such use as skin-bleaching agents, mercury compounds have also been widely used as preservatives in cosmetics such as hand and body creams and lotions; hair shampoos, hair sets and rinses, hair straighteners, hair coloring, and other preparations; bath oils, bubble bath, and other bath preparations; makeup; antiperspirants and deodorants; and eye-area cosmetics.

(b) The toxicity of mercury compounds is extensively documented in scientific literature. It is well known that mercury compounds are readily absorbed through the unbroken skin as well as through the lungs by inhalation and by intestinal absorption after ingestion. Mercury is absorbed from topical application and is accumulated in the body, giving rise to numerous adverse effects. Mercury is a potent allergen and sensitizer, and skin irritation is common after topical application. Cosmetic preparations containing mercury compounds are often applied with regularity and frequency for prolonged periods. Such chronic use of mercury-containing skin-bleaching preparations has resulted in the accumulation of mercury in the body and the occurrence of severe reactions. Recently it has also been determined that microorganisms in the environment can convert various forms of mercury into highly toxic methyl mercury which has been found in the food supply and is now considered to be a serious environmental problem.

(c) The effectiveness of mercury-containing preparations as skin-bleaching agents is questionable. The Food and Drug Administration has not been provided with well controlled studies to document the effectiveness of these preparations. Although mercurial preservatives are recognized as highly effective, less toxic and satisfactory substitutes are available except in the case of certain eye-area cosmetics.

(d) Because of the known hazards of mercury, its questionable efficacy as a skin-bleaching agent, and the availability of effective and less toxic nonmercurial preservatives, there is no justification for the use of mercury in skin-bleaching preparations or its use as a preservative in cosmetics, with the exception of eye-area cosmetics for which no other effective and safe nonmercurial preservative is available. The continued use of mercurial preservatives in such eye-area cosmetics is warranted because mercury compounds are exceptionally effective in preventing Pseudomonas contamination of cosmetics and Pseudomonas infection of the eye can cause serious injury, including blindness. Therefore:

(1) The Food and Drug Administration withdraws the opinion expressed in trade correspondence TC–9 (issued May 13, 1939) and concludes that any product containing mercury as a skin-bleaching agent and offered for sale as skin-bleaching, beauty, or facial preparation is misbranded within the meaning of sections 502(a), 502(f)(1) and (2), and 502(j), and may be a new drug without approval in violation of section 505 of the Federal Food, Drug, and Cosmetic Act. Any such preparation shipped within the jurisdiction of the Act after January 5, 1973 will be the subject of regulatory action.

(2) The Food and Drug Administration withdraws the opinion expressed in trade correspondence TC–412 (issued Feb. 11, 1944) and will regard as adulterated within the meaning of section 601(a) of the Act any cosmetic containing mercury unless the cosmetic meets the conditions of paragraph (d)(2) (i) or (ii) of this section.

(i) It is a cosmetic containing no more than a trace amount of mercury and such trace amount is unavoidable under conditions of good manufacturing practice and is less than 1 part per million (0.0001 percent), calculated as the metal; or

(ii) It is a cosmetic intended for use only in the area of the eye, it contains no more than 65 parts per million (0.0065 percent) of mercury, calculated as the metal, as a preservative, and there is no effective and safe nonmercurial substitute preservative available for use in such cosmetic.

Offline nandaz

  • Profesor
  • *****
  • Tulisan: 1.849
  • IQ: 75
  • Gender: Pria
  • ...Mad about Sci_mistery
Re: Raksa (Hg)
« Jawab #20 pada: Februari 12, 2009, 04:46:16 AM »
...hya,

 tapi disamping itu penyerapan raksa terhadap panas amat bagus, sehingga termometer bermaterial raksa murni yang putih mengkilat cendrung banyak.
....ada seorang teman yang bertanya pada saya begini  "Selain air raksa, kan masih ada logam lain yang juga berupa cairan dalam suhu ruang yaitu GALIUM(Ga). Bagaimana kelebihan dan kelemahan galium jika dipakai sebagai pengisi termometer. Mana yang lebih baik, galium atau air raksa ?"

 nah, ada masukan...? soalnya aku ngga bisa ngejawab...
« Edit Terakhir: Februari 12, 2009, 04:48:45 AM oleh nandaz »

Offline syx

  • Global Moderator
  • Profesor
  • *****
  • Tulisan: 4.540
  • IQ: 341
  • Gender: Pria
    • Kliping Koran
Re: Raksa (Hg)
« Jawab #21 pada: Februari 12, 2009, 07:13:34 AM »
galium titik leburnya sekitar 30oC, jadi ga dipake untuk termometer ruang biasa. bisa dipake untuk termometer suhu tinggi karena titik didihnya sekitar 2200oC.

Offline Ief-Tha

  • Mahasiswa
  • **
  • Tulisan: 34
  • IQ: 4
  • Gender: Wanita
  • "Un bienfait n'est jamais perdu...">
Re: Raksa (Hg)
« Jawab #22 pada: Februari 21, 2009, 02:06:25 AM »
Kurang tw, z...
But, AnyThing is PossibLe!!!
zAw, kHan??? ^_^ ;)
"You only live once, but if you do it right, once is enough"

Offline nandaz

  • Profesor
  • *****
  • Tulisan: 1.849
  • IQ: 75
  • Gender: Pria
  • ...Mad about Sci_mistery
Re: Raksa (Hg)
« Jawab #23 pada: Februari 21, 2009, 04:51:58 AM »
Kurang tw, z...
But, AnyThing is PossibLe!!!
zAw, kHan??? ^_^ ;)
hei, kalo mau tanya tentang raksa tulis disini...siapa tau dapat saling kasih ilmu, yang ngga taunya dimana?

Offline Gari Gomes

  • Mahasiswa
  • **
  • Tulisan: 11
  • IQ: 8
  • Gender: Pria
Re: Raksa (Hg)
« Jawab #24 pada: Maret 11, 2009, 08:48:14 AM »

Istilah logam berat sebenarnya untuk menyebut sejumlah unsur. Disebut logam berat lantaran berat molekulnya lebih besar dibandingkan dengan unsur-unsur kimia lainnya.

Offline biobio

  • Moderator
  • Profesor
  • *****
  • Tulisan: 2.476
  • IQ: 221
  • Gender: Pria
  • Tjiasmanto, Wewin
Merkuri Untuk Menambang Emas
« Jawab #25 pada: April 19, 2009, 04:30:29 AM »
Bagaimana teknik memisahkan emas dari kotorannya menggunakan merkuri? Thanks
"The pen is mightier than the sword"

Offline skuler

  • Staff
  • Profesor
  • *****
  • Tulisan: 993
  • IQ: 109
  • Gender: Pria
  • Read! write! Revolt!
    • Read! write! Revolt!
Re: Merkuri Untuk Menambang Emas
« Jawab #26 pada: April 19, 2009, 08:35:54 PM »
merkuri bisa memisahkan emas dari pengotor2nya. hmm... sepertinya ada hubungannya dengan kohesi dan adesi... ato gmana? gw jg kurang ngerti. ada yg bisa bantu?
"Who controls the present now controls the past. Who controls the past now controls the future.”-- RATM, 1999.

Offline syx

  • Global Moderator
  • Profesor
  • *****
  • Tulisan: 4.540
  • IQ: 341
  • Gender: Pria
    • Kliping Koran
Re: Raksa (Hg)
« Jawab #27 pada: April 21, 2009, 07:44:30 AM »
sorry... gw gabung topiknya ke sini ya. untuk alasan mengapa merkuri dipake dalam tambang emas ada di halaman satu.

Offline Muztank

  • Dosen
  • ****
  • Tulisan: 410
  • IQ: 27
  • Gender: Pria
  • biotek...^^
Re: Raksa (Hg)
« Jawab #28 pada: April 22, 2009, 02:06:20 AM »
trus jawabannya apa?

Offline syx

  • Global Moderator
  • Profesor
  • *****
  • Tulisan: 4.540
  • IQ: 341
  • Gender: Pria
    • Kliping Koran
Re: Raksa (Hg)
« Jawab #29 pada: April 27, 2009, 11:01:50 PM »
2. masa sih Hg bersifat korosif? cuma garam tertentu aja kan? merkurinya sendiri ga. bahan ini cuma mudah membentuk amalgam dengan logam lain, seperti emas, perak, dan timah. makanya dipake dalam pertambangan emas untuk menarik emas dari bijihnya.
... dari halaman 1.