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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: trickay on September 24, 2005, 12:30:20 AM

Title: Unharmful elements becoming harmful compounds
Post by: trickay on September 24, 2005, 12:30:20 AM

Hi, I need an example of two unharmful elements (to humans), that come together to make a harmful compound (to humans).

Thanks in advance.

Title: Re:Unharmful elements becoming harmful compounds
Post by: xiankai on September 24, 2005, 03:39:07 AM

there are plenty of dangerous compounds around. stretch your imagination abit more. the air we breath in, for example.

Title: Re:Unharmful elements becoming harmful compounds
Post by: Karakth on September 24, 2005, 10:28:53 AM

Sounds almost like you want to make poison at home...

Title: Re:Unharmful elements becoming harmful compounds
Post by: trickay on September 24, 2005, 10:37:20 AM

Quote from: xiankai on September 24, 2005, 03:39:07 AM

there are plenty of dangerous compounds around. stretch your imagination abit more. the air we breath in, for example.

Yeah, but the difference is I need the dangerous compound to be composed of unharmful elements.

I thought I had it with Chlorine and Sodium becoming table salt, but then I realized I was doing it backwards  :D.

Title: Re:Unharmful elements becoming harmful compounds
Post by: Borek on September 24, 2005, 11:42:33 AM

So stick to C, H, N and O and check how you can kill yourself with compounds made with these elements ;)

Title: Re:Unharmful elements becoming harmful compounds
Post by: Karakth on September 24, 2005, 04:31:37 PM

Ok, here's what you do:

You take some innocent carbohydrate (like starch, found in foods like pasta, bread, etc) and react it in limited O₂ (some heat may be required to overcome the activation energy of the reaction) to produce polymers of benzene.

These benzene polymers can then be dispersed into the air. They are very potent carcinogens when inhaled.

Title: Re:Unharmful elements becoming harmful compounds
Post by: xiankai on September 24, 2005, 08:03:17 PM

i doubt carbohydrates qualify as an element, though  :-\

borek's suggestion is a great one

Title: Re:Unharmful elements becoming harmful compounds
Post by: Mitch on September 24, 2005, 10:31:30 PM

O3

Title: Re:Unharmful elements becoming harmful compounds
Post by: Karakth on September 25, 2005, 05:34:26 AM

Oh right he wanted elements.

Seems logical then to go with Carbon and Nitrogen, and make CN.

Title: Re:Unharmful elements becoming harmful compounds
Post by: Donaldson Tan on October 11, 2005, 06:45:38 PM

harmless element A + harmless element B => toxic compound C

what are A, B and C?

A and B can't be nitrogen and carbon because  CN does not exist. You need a third element in the compound. eg. HCN, NaCN, KCN.

Here's some I can think of:
Carbon + Oxygen => Carbon Monoxide

But it all boils down to the criteria for what's not harmful to humans.

sulphur is harmless to touch, toxic to eat.
pure hydrogen is a fire hazard
pure oxygen is corrosive and is also a fire hazard.
liquid nitrogen gives u cold burn..

Title: Re:Unharmful elements becoming harmful compounds
Post by: jdurg on October 11, 2005, 11:01:07 PM

Nitrogen + Oxygen => Nitric Oxide.  

Title: Re:Unharmful elements becoming harmful compounds
Post by: mithrilhack on October 12, 2005, 01:41:07 AM

cyanides

scn

Title: Re:Unharmful elements becoming harmful compounds
Post by: jdurg on October 12, 2005, 09:51:38 AM

Quote from: mithrilhack on October 12, 2005, 01:41:07 AM

cyanides

scn

SCN is actually the thiocyanide ion and really isn't that toxic or dangerous.  Plus, it must have a counter-ion to it so you'd need Fe, or Na, or K in there.