Chemistry thread <No trash spams plz>

Hi all. Bagi yg ada pertanyaan ttg kimia blh di-post di sini. Kalo bisa gw bantu, gw jwb kok Atau ttg perkembangan baru di bdg kimia juga blh. Welcome2

Best regards,
tatsu88

gmn tentuin kl suatu compound itu amphotermic,acidic,basic ato neutral?kasi contohnya donk...thx.

Pertanyaan ini hari itu Nita ada tanya gw. Acidic en basic cukup mdh. Reaksikan unsurnya dgn air. Misalnya:

H2SO4 + H2O --> HSO4- + H3O+

KOH + H2O --> K+ + 2OH- + H+
Jadi H2SO4 itu acid compound & KOH itu basic compound.


Neutral compound itu kebykan garam atau ionic salt, covalent compound, and complex compound. Neutral compound itu walaupun dilarutkan dlm air, tdk akan membentuk unsur baru, tetapi hanya akan larut dlm air.


NaCl + H2O --> nothing happened



Amphoteric compound itu bisa membentuk ion asam atau basa dan umumnya mengandung unsur Be, B, Al dan amphoteric metal yg lain. Dan spt biasa, reaksikan dgn air:



Al2O3 + H2O --> 2H3AlO3

Al2O3 + H2O --> 2Al(OH)3

Kalo ada yg salah, tlg beritahu. Thx.

(tatsu88)

amphoteric metal itu apa aja?
soalnya kl w search tuh cuma Al,Be,Sn,Zn,Pb,metalloid,amino acid,protein and water.
and in some cases ada bbrp tuh bkn amphoteric,bs dijelaskan?

Menjadi asam atau basa itu tergantung dgn keadaan sekitarnya misalnya pH atau adanya interaksi dgn ion/unsur lain. Misalnya amino acid (H2N-CHR-COOH, dgn R adalah substitusi alkyl, dll). Yg berikatan dgn basa nantinya adalah konjugasi asamnya : NH3+ dlm [+H3N]-CHR-[COO-] dan yg berikatan dgn anion asam nantinya adalah konjugasi basanya : COO-. Sdgkan utk unsur misalnya H2O. Konjugasi asamnya adalah H3O+ dan konjugasi basanya adalah OH-.

Cth bkn amphoteric adalah pd saat unsur dlm keadaan tingkat oksidasi plg tinggi atau pd nilai pH tertentu amphoteric propertynya itu tdk berlaku (biasanya dlm protein,amino acid pH sgt berperan penting). Utk metalloid dan unsur2 transisi, amphoteric property itu bergantung pd suhu dan tekanan saat reaksi atau proses itu berlgsg.

Utk lbh pasti dan lengkapnya, wikipedia sgt membantu kok. Maaf kalo tdk dpt bantu byk.

(tatsu88)

thx...

Terus Reaksi coca-cola tuh kan berbahaya bagi tubuh?
koq maci ada yg mau minum?
katanya klo masukin barang,lama2 bisa ilang n teroksidasi ya?
weks..tar usus kita ilang jg dunk>?

boyzmedan wrote:

Terus Reaksi coca-cola tuh kan berbahaya bagi tubuh?
koq maci ada yg mau minum?
katanya klo masukin barang,lama2 bisa ilang n teroksidasi ya?
weks..tar usus kita ilang jg dunk>?

http://www.perlmonks.org/?node_id=306626

Actually, there is a fair amount of misinformation in the coke part of that article. To wit:
3. To clean a toilet, pour a can of Coca-Cola into the toilet bowl and let the "real thing" sit for one hour, then flush clean. The citric acid in Coke removes stains from vitreous china.
Citric acid is totally harmless. In fact, citric... citric... sounds like... citrus.... Imagine that, coke has the same acid as oranges. The majority of energy for all mammals is produced in the "citric acid cycle".
4. To remove rust spots from chrome car bumpers : rub the bumper with a crumpled-up piece of Reynolds wrap aluminum foil dipped in Coca-Cola.
Interesting, I didn't know that. The Coke must be acting as a conduit for ion-transfer from the bumper to the more electropositive aluminum. Hmm... salt water would work too. As would any other highly ionic solution, for that matter. I imagine the key factor is the specific activity, so the doubly charged PO4(2-) will make coke great for this. Fortunately we don't have electrodes in our stomach.
5. To clean corrosion from car battery terminals : pur a can of Coke-Cola over the terminals to bubble away the corrosion.
See above coke acts as a great hydrogen donor to help displace any unwelcome oxidation.
6. To loosen a rusted bolt: apply a cloth soaked in Coca-Cola to the rusted bolt for several minutes.
See above
7. To remove grease from clothes, Empty a can of coke into a load of greasy clothes, add detergent and run through a regular cycle. The Coca-Cola will help lossen grease stains. it will also clean road-haze from your windshield.
I didn't know this, and to be honest I can't see why coke is acting as a surfactant. That's interesting: I wonder if it would work for any low-pH solutions?
1. The active ingredient in Coke is phosphoric acid. Its pH is 2.8. It will dissolve a nail in about 4 days.
Inorganic Phosphorus (PPi) is one of the driving forces for ATP synthesis. The body uses phosphoric acid extensively as a buffer to control cellular pH.
2. To carry Coca-Cola syrup (the concentrate) the commercial truck must use the Hazardous material place cards reserved for Highly corrosive materials.
So lets say that they dilute the syrup 10x to made a glass. That makes the syrup pH 1.8, explaining that. When you dilute the acid. So?


The basic fact is true: water is better for you than Coke. We should all drink a lot more water than we do. But I don't think scaring people by throwing a lack of chemistry in their face is a good way to do it; the benefits of water should stand on their own. I think the references to citric and phosphoric acid are in particularly poor taste: those are essential constituents of the all eukaryotes. They aren't "bad chemicals" in any way shape or form. [quoted from website above]

Satu hal yg saya mau katakan di sini adalah mslh komersial. Sama spt formalin yg terdpt dlm mie, bbrp zat yg dimksd zat pengoksidasi tsb sebnrnya mmg diproduksi oleh tubuh dlm jlh tertentu yg diperlukan. Misalnya formalin. Formalin itu adalah produk sampingan dr reaksi di dlm tubuh & segera bisa diubah menjadi unsur lain dlm bbrp saat saja. Sdgkan % formalin yg ada dlm mie itu bisa dikatakan sama jlhnya dgn yg diproduksi dlm tubuh. Mmg sebaiknya jgn dikonsumsi tetapi kan tdk mslh. Mslh paku yg bisa hilang teroksidasi dlm 4 hari itu mmg bnr & ada disinggung di dlm website di atas. Salah satu asam dlm Coca Cola adalah phosphoric acid & citrus acid. Di dlm lab pun saya tkt dgn phosphoric acid wlaupun merupakan asam lemah tapi tingkat oksidasinya sgt tinggi dgn pH<3-4. Tetapi tubuh kita sendiri juga memproduksi asam ini tetapi tdk berbahaya (ada dijlskan di website tadi mengapa tdk berbahaya)

Jadi nasehat saya, sebaiknya jgn termkn oleh berita2 sains yg tdk bnr apalagi kimia. Mmg hal itu bisa terjadi tetapi mslhnya di sini, jlh dr unsur itu hanya sedikit & tdk berbahaya dlm tubuh kita. Sekian. Kalo misalnya ada kontroversial yg baru ttg mslh ini atau ada yg salah, tlg di-post. Thx.

(tatsu88)

mau tanya, apa kah coca cola di campur sama mentos, di bilang akan meledak, apa benar itu ???

Itu mmg bnr. Lht aja di wikipedia. Itu terjadi karena gas karbondioksida yg ada di dlm Coca Cola menghasilkan gelembung (bubble) dan kemudian air tertekan dan keluar spt geyser atau air mancur.

(tatsu88)