2015年7月29日 · A much more comprehensive quantitative description is given here for the LD$_{50}$ of coffee for an 80 kg person (113 cups at 250 mL each, 135 mg caffeine per serving). They account for half-life of elimination of caffeine, and arrive a the conclusion that one can't actually reach the LD$_{50}$ (15,360 mg) for caffeine due to metabolism ...

2020年7月28日 · Organic mercury is extremely toxic (about 10 times worse than arsenic), and it has an LD50 of about 0.1 g, so that's probably a reasonable upper limit for any other heavy metal such as plutonium. 239Pu's radioactivity is in the form of alpha particles, which are only dangerous if emitted internally, because they can't penetrate the epidermis.

2018年1月16日 · Actual LD50 is around 90 ng for humans for acute radiation disease. Antimatter: looks like around 1 ng would be plenty to kill a person. LD50 would be much lower, but probably easy enough to measure anyway. Real problem in the experiment would be delivering the antimatter without premature annihilation.

2013年12月18日 · Anhydrous caffeine occurs in two different polymorphic crystal forms, with a transition between the two forms occurring at $\pu{136 °C}.$ The high temperature form has a melting point of $\pu{236 °C}.$ The vapor pressure of the high temperature solid form is described by the equation: $$\log P[\pu{Pa}] = -\frac{5477}{T[\pu{K}]} + 14.395,\tag{1}$$

2014年10月17日 · Also, caffeine isn't even a major component of brewed coffee, only accounting for ~1% of the dry mass. If you look here you'll see that brewed and green coffee naturally contains a fair bit of soluble acids, including things like nicotinic acid (vitamin B3), which probably accounts for the pH of brewed coffee, rather than the caffeine or any ...

The MSDS gives oral LD50 values. That is, the lethal dose required to kill half the population. The LD50 for soaps seem to vary by animal, but judging from a few MSDS I pulled up, they're ~2 g/kg or so. (That value was for rats.) So if I had to guess, given, say a ~70 kg adult, we'd be talking about 140 g of soap, minimum to kill a person.

2016年8月17日 · Does the brewing temperature have an effect on the caffeine level? For instance, coffee with 100*C have higher caffeine level compared to coffee with 50*C?

Next, I perform the extraction of caffeine using standard procedures (separate by dichloromethane and evaporate). I was able to extract ~80mg of caffeine in 70-degree celsius water. I redissolve the powder into water to a 100 mL volumetric flask. I then pipette 25mL of the caffeine and added excess $\ce{I2}$ and $\ce{H2SO4}$.

2015年7月16日 · Every sufficiently asymmetric molecule will be polar, but some more than others. The polarity of molecules is related to the polarity of bonds within the molecule, but just having polar bonds is not enough to create a polar molecule.

2022年12月23日 · Potassium_ferrocyanide $\ce{K4[Fe(CN)6]}$ has LD50 $\pu{6400 mg/kg}$ (oral, rat), what would be about $\pu{500 g}$ for $\ce{75 kg}$ person, assuming the same LD50. $\ce{NaCl}$ has LD50 $\pu{3000 mg/kg}$ (oral,rat). Silver cyanide AgCN is hardly used, being insoluble. It would be soluble potassium silver cyanide K[Ag(CN)2](commercially available ...