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 2020-10-20, 14:30 #67 Dr Sardonicus     Feb 2017 Nowhere 3,881 Posts The (approximate) molecular weight of the asphyxiant CO is 12 + 16 = 28, which is the same as the 14 + 14 of N2, which is by far the largest component of air. (The next-largest is oxygen, with a molecular weight near 32.) So, in addition to being colorless and odorless, carbon monoxide is almost neutrally buoyant in air. Methane, the principal component of natural gas, is colorless and odorless. With a molecular weight of 12 + 4 = 16, it is considerably lighter than air. Nonetheless, it can easily mix with air to form an explosive mixture, as it often does in coal mines, where it was long known as "firedamp." (The "damp" is from the German Dampf, vapor.) It was dreaded for the mine explosions it caused, which came without warning. With the distribution of odorless flammable gas for domestic and commercial use came the danger of similar explosions due to leaks. Gas was first "odorized" in Germany in the 1880's to make gas leaks easily detectable. Today's familiar "gas smell" is due to the addition of an "odorant," usually isporopyl mercaptan, often mixed with tert-butyl mercaptan. Here in the USA, odorization of gas only became widespread after the New London, TX school explosion in 1937. It leveled the building and killed almost 300 school kids.
2020-10-21, 06:12   #68
LaurV
Romulan Interpreter

Jun 2011
Thailand

213718 Posts

Quote:
 Originally Posted by Dr Sardonicus The (approximate) molecular weight of the asphyxiant CO is 12 + 16 = 28, which is the same as the 14 + 14 of N2, which is by far the largest component of air. (The next-largest is oxygen, with a molecular weight near 32.) So, in addition to being colorless and odorless, carbon monoxide is almost neutrally buoyant in air.
(my emphasis)

That may be factually true, but the logic is leaking. Molar weight has nothing to do with buoyancy. The density, does.

2020-10-21, 06:48   #69
S485122

Sep 2006
Brussels, Belgium

32·181 Posts

Quote:
 Originally Posted by LaurV (my emphasis) That may be factually true, but the logic is leaking. Molar weight has nothing to do with buoyancy. The density, does.
Never heard of Avogadro's "law" : a mole of a gas has the same volume at a given temperature and pressure whatever the gas. In other words he molecular weight gives a very good idea of the density.

Jacob

Last fiddled with by S485122 on 2020-10-21 at 06:52 Reason: fiddled a bit and Boyle's law is some other aspect of an "ideal" gas.

 2020-10-21, 07:05 #70 LaurV Romulan Interpreter     Jun 2011 Thailand 213718 Posts yep Brain fart... $$\rho=\frac{P\mu}{RT}$$ I was good at chemistry and thermodynamics in high school... But that was last century... Getting older and stupider (and too eager to catch Dr.S. in offside haha). Last fiddled with by LaurV on 2020-10-21 at 07:07
2020-10-21, 10:37   #71
a1call

"Rashid Naimi"
Oct 2015
Remote to Here/There

36328 Posts

Quote:
 Originally Posted by S485122 Never heard of Avogadro's "law" : a mole of a gas has the same volume at a given temperature and pressure whatever the gas. In other words he molecular weight gives a very good idea of the density. Jacob
Avocados can be poisonous to horses. Nasty stuff.

https://ker.com/equinews/avocados-can-toxic-horses/

2020-10-21, 12:26   #72
Dr Sardonicus

Feb 2017
Nowhere

3,881 Posts

Quote:
Originally Posted by a1call
Quote:
 Originally Posted by S485122 Never heard of Avogadro's "law" : a mole of a gas has the same volume at a given temperature and pressure whatever the gas. In other words he molecular weight gives a very good idea of the density. Jacob
Avocados can be poisonous to horses. Nasty stuff.

https://ker.com/equinews/avocados-can-toxic-horses/
Based on the xkcd "What if?..." A mole of moles, we have

6.02214076 x 1023 avocados = Planet Guacamole

 2020-10-21, 14:22 #73 a1call     "Rashid Naimi" Oct 2015 Remote to Here/There 2·7·139 Posts I think it's time to change my hearing aid's battery. Apologies for the misunderstanding.
2020-10-24, 19:47   #74
a1call

"Rashid Naimi"
Oct 2015
Remote to Here/There

2·7·139 Posts

Quote:
 This plant has small, lateral leaflets which move at speeds rapid enough to be perceivable with the naked eye. This is possibly a strategy to maximise light by tracking the sun.[2][3] Each leaf is equipped with a hinge that permits it to be moved to receive more sunlight, but the weight of these leaves means the plant must expend a lot of energy in moving it. To optimise its movement, each large leaf has two small leaflets at its base. These move constantly along an elliptical path, sampling the intensity of sunlight, and directing the large leaf to the area of most intensity.
https://en.m.wikipedia.org/wiki/Codariocalyx_motorius

Realtime video:

https://youtu.be/Ta4I5Uwv9m0

Last fiddled with by a1call on 2020-10-24 at 19:51

2020-10-25, 21:28   #75
a1call

"Rashid Naimi"
Oct 2015
Remote to Here/There

2×7×139 Posts

Quote:
 Tardigrades, which are also known as space bears or moss piglets, are able to survive for up to 30 years without food or water and endure temperature extremes of up to 150 degrees celsius, the deep sea and the frozen vacuum of space.

https://www.telegraph.co.uk/science/...l-alive-earth/

Quote:
 Temperature – tardigrades can survive: A few minutes at 151 °C (304 °F)[51] 30 years at −20 °C (−4 °F)[52] A few days at −200 °C (−328 °F; 73 K)[51] A few minutes at −272 °C (−458 °F; 1 K)[53]
https://en.m.wikipedia.org/wiki/Tardigrade

Last fiddled with by a1call on 2020-10-25 at 21:36

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