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KNO3 - NaNO3?

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Renesis

Thu Jan 28 2010, 01:57PM

Registered Member #2028 Joined: Mon Mar 16 2009, 08:13PM
Location: Norway
Posts: 319

Hi. Today my teacher told us stories from his youth, when they used to make rockets out of newspapers dipped in a saltpetre/water solution. Then he went on to write up saltpetre's chemical formula; NaNO3. But from what i can recall saltpetres chemical formula is KNO3, not NaNO3. A quick google search and 4hv site search revealed that the two salts are often mentioned in the same sentence, but i failed to find the real difference between them. What they are used for, where they are found and such.

Which one of these substances is known as saltpetre, and what is the main difference between them?

MinorityCarrier

Thu Jan 28 2010, 04:43PM

Registered Member #2123 Joined: Sat May 16 2009, 03:10AM
Location: Bend, Oregon
Posts: 312

From my childhood memory, both potassium nitrate and sodium nitrate were lumped together as salt peter. These days postassium nitrate is thought of as salt peter.

I remember buying sodium nitrate from a hobby shop when I was a kid, and it would have the words "Salt Peter" in parenthesis on the bottle.

the original moniker "Salt Peter" is just a medieval name for the salt seperated out from the processing of urine and feces back in ye goode olde days. They didn't know there were two different salts in there.

If you want to have some real excitement, soak a roll of newspaper in sodium chlorate solution and light that after it drys.

Bored Chemist

Thu Jan 28 2010, 06:33PM

Registered Member #193 Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022

"f you want to have some real excitement, soak a roll of newspaper in sodium chlorate solution and light that after it drys."
carefully and outside on something that wno't burn.

Anyway, NaNO3 is "Chile saltpeter".

Andri

Thu Jan 28 2010, 06:35PM

Registered Member #1533 Joined: Wed Jun 11 2008, 02:13PM
Location: ReykjavÃk, Iceland
Posts: 46

From http://en.wikipedia.org/wiki/Sodium_nitrate

Sodium nitrate is the chemical compound with the formula NaNO3. This salt, also known as "Chile saltpeter" or "Peru saltpeter" (to distinguish it from ordinary saltpeter, potassium nitrate), is a white solid which is very soluble in water. The mineral form is also known as nitratine or soda niter.

So, there is a distinction according to Wikipedia.

Renesis

Thu Jan 28 2010, 06:52PM

Registered Member #2028 Joined: Mon Mar 16 2009, 08:13PM
Location: Norway
Posts: 319

So, KNO3 is saltpeter and NaNO3 is "Chile" saltpeter. It seems to me that these two substances are used in the same way, and performs nearly identical. Is that correct?

Adrenaline

Thu Jan 28 2010, 06:59PM

Registered Member #235 Joined: Wed Feb 22 2006, 04:59PM
Location:
Posts: 80

The sodium salts tend to be more hydrophilic, especially the chlorate salt.

MinorityCarrier

Thu Jan 28 2010, 09:00PM

Registered Member #2123 Joined: Sat May 16 2009, 03:10AM
Location: Bend, Oregon
Posts: 312

Potassium nitrate generally produces a faster deflagration in home made black powder than sodium nitrate.

Sodium nitrate will produce an intense orange flame, potassium nitrate produces a lavendar-ish colored flame, useful in colored pyrotechnics.

Good thing the country of Chile came into existance and included the Atacama desert, otherwise it might be tough figuring out which salt peter was which.

radhoo

Sat Feb 20 2010, 12:59PM

Registered Member #1938 Joined: Sun Jan 25 2009, 12:44PM
Location: Romania
Posts: 699

actually NaNO3 is called Chile saltpeter while KNO3 is India salpeter.

radiotech

Sun Feb 21 2010, 05:05AM

Registered Member #2463 Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546

Saltpeter Chile is NaNO3
Saltpeter Nitre is KNO3
Niter is a commercial chemical name for KNO3
Agricultural fertilizers prior to Haber.

quicksilver

Tue Feb 23 2010, 12:23AM

Registered Member #1408 Joined: Fri Mar 21 2008, 03:49PM
Location: Oracle, AZ
Posts: 679

The toughest thing about any rocket is getting the thrust to "focus" it's direction. Both NaNO3 and KNO3 (and some fuel materiel like sugar, etc) is capable of thrust. The issue is what is known as a nozzle. This is generally a non-burnable materiel that directs the thrust of the burning propellant to a point wherein it lifts the device as a whole.

Basically they are made from clay or in some more sophisticated concepts a plug of graphite with a hole. The design of the propellant is also a factor. It must burn at a rate that allows maximum push.
This is more complex than it may seem at first. I have actually seen a little rocket made from a match! The nozzle CAN BE part of the fuel but the start of the combustion is primary to a nozzle-less rocket design. In many rockets, designers use tooling to compress the propellant this alters the burn rate. The fuel itself alters the burn rate. many factors come into play when making rockets and it can be a Hell of a lot of fun!

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