Hello loyal chemistry fans! I apologise for my long absence on the blog scene but it has been a busy two months in the world of this graduate student. Today's entry is a word lesson brought on by its confusing nature: inflammability.
I don't know about you, but every time I hear the word "inflammable" I think it means "not flammable". This would be very, VERY wrong.
Inflammable: (Merriam-Webster's Online Dictionary) 1) Flammable 2) Easily inflamed, ignited, or angered
Along with the word "inflammable" another important term to understand is "flash point". I am not talking about Canadian show with the Pink Ranger in it. I am referring to the lowest temperature at which a volatile liquid can vapourise, and therefore ignite, in air. This is really important to understand because it explains why you don't talk on a cell phone at a gas station or smoke while pouring out diethyl ether. An inflammable liquid is one that is considered to have a flash point below 37.8 degrees C (as stated in the Alberta Fire Code).
The flash point of gasoline is -43 degrees C. This is why here in Edmonton in the middle of winter we are still able to drive our cars. (It may be of interest to those readers who are not from the Canadian prairies to know that the coldest temperature recorded in Edmonton was -49.4 degrees C-and that does NOT include the windchill.) The point I am trying to make here is that knowledge of the flash point is crucial to the function of a combustion engine. It is also important to know when you are filling up engine with said fuel. Because the average temperatures that gasoline is stored at is well above its flash point, it doesn't take that much to volatilise to an ignitable mixture. And it so happens that electric charge from a cell phone may be enough to spark, and therefore set fire to, the gasoline you are trying to get into your car. Diethyl ether has a flash point of -45 degrees C. It is possible for static build up in the solvent bottle to cause this particular solvent to burst into flames.
If you don't believe me that static charge could actually set fire to something, let me tell you a story. The scariest lab moment for me occurred a few weeks ago when I was weighing out ruthenium dioxide hydrate. This is a pretty innocuous substance. (The "hydrate" part means that it has water in it and therefore should not be a fire threat.) I grabbed a flask and washed it out with acetone and water-not a problem because the solvents I planned to use in this reaction were acetone and water. When I added the ruthenium dioxide to the flask a ball of fire came spurting out the top. (No worries, it quickly burnt itself out, but the three seconds of flame left me a little jumpy the rest of the day.) THERE IS NO CHEMICAL REASON FOR THIS. Check the MSDS: ruthenium dioxide hydrate is a really safe chemical (all things considered). So what happened? My hypothesis: the flash point of acetone is -20 degrees C. There was enough heat created by the dissolution of the ruthenium dioxide hydrate in the small amount of water left in the flask that it was able to ignite the small amount of acetone vapours still remaining in the flask.
The moral of the story: that sign at the gas station about not talking on your cell phone or having a smoke is not there just because the owners feel that talking on your phone while using their services is rude or they don't like the smell of cigarette smoke. It is there because of your safety and that of others.
Along with the word "inflammable" another important term to understand is "flash point". I am not talking about Canadian show with the Pink Ranger in it. I am referring to the lowest temperature at which a volatile liquid can vapourise, and therefore ignite, in air. This is really important to understand because it explains why you don't talk on a cell phone at a gas station or smoke while pouring out diethyl ether. An inflammable liquid is one that is considered to have a flash point below 37.8 degrees C (as stated in the Alberta Fire Code).
The flash point of gasoline is -43 degrees C. This is why here in Edmonton in the middle of winter we are still able to drive our cars. (It may be of interest to those readers who are not from the Canadian prairies to know that the coldest temperature recorded in Edmonton was -49.4 degrees C-and that does NOT include the windchill.) The point I am trying to make here is that knowledge of the flash point is crucial to the function of a combustion engine. It is also important to know when you are filling up engine with said fuel. Because the average temperatures that gasoline is stored at is well above its flash point, it doesn't take that much to volatilise to an ignitable mixture. And it so happens that electric charge from a cell phone may be enough to spark, and therefore set fire to, the gasoline you are trying to get into your car. Diethyl ether has a flash point of -45 degrees C. It is possible for static build up in the solvent bottle to cause this particular solvent to burst into flames.
If you don't believe me that static charge could actually set fire to something, let me tell you a story. The scariest lab moment for me occurred a few weeks ago when I was weighing out ruthenium dioxide hydrate. This is a pretty innocuous substance. (The "hydrate" part means that it has water in it and therefore should not be a fire threat.) I grabbed a flask and washed it out with acetone and water-not a problem because the solvents I planned to use in this reaction were acetone and water. When I added the ruthenium dioxide to the flask a ball of fire came spurting out the top. (No worries, it quickly burnt itself out, but the three seconds of flame left me a little jumpy the rest of the day.) THERE IS NO CHEMICAL REASON FOR THIS. Check the MSDS: ruthenium dioxide hydrate is a really safe chemical (all things considered). So what happened? My hypothesis: the flash point of acetone is -20 degrees C. There was enough heat created by the dissolution of the ruthenium dioxide hydrate in the small amount of water left in the flask that it was able to ignite the small amount of acetone vapours still remaining in the flask.
The moral of the story: that sign at the gas station about not talking on your cell phone or having a smoke is not there just because the owners feel that talking on your phone while using their services is rude or they don't like the smell of cigarette smoke. It is there because of your safety and that of others.
