experimental chemistry - What is the purpose of a boiling stick …
2018年3月20日 · The boiling chip is serving a similar purpose to the solute being introduced to a supersaturated solution. In order for the precipitation to begin happening, it requires enough of the precipitating material to overcome the viscosity of the solvent and join together into its own unit.
Reusing boiling chips - Chemistry Stack Exchange
2017年1月28日 · Boiling chips and stones are only used once, as the absorptive material becomes impregnated with the first solvent used in. And Wikipedia confirms the basic idea of why they shouldn't be used more than once: The structure of a boiling chip traps liquid while in use, meaning that they cannot be re-used in laboratory setups.
Boiling chips for concentrating sulfuric acid
2019年7月14日 · If the liquid has been cooled down, make sure to add at least one new chip before heating again to the boiling point (prevents superheating). Avoid using boiling chips for vacuum distillation. Instead, use mechanical stirring or bubble inert gas (argon, nitrogen) through a submerged glass capillary. Boiling chips don't work under vacuum.
everyday chemistry - What would explain urine that resists …
$\begingroup$ Add a tiny jot of ground glass, a boiling chip, or scratch the side of the container with a glass stir rod. You need nucleation centers. $\endgroup$ – Uncle Al
Double Deionized Water and Superheating - Chemistry Stack …
2014年6月17日 · This why boiling chips are commonly used in lab distillations. They provide a site for vapor nucleation and usually prevent superheating of the material to be distilled. Introducing other sites for nucleation, such as dissolved bubbles, solid contaminants, rough spots on the wall of the container all serve to lessen the probability of superheating.
experimental chemistry - Practices while using a boiling tube ...
2021年5月19日 · These "boiling tubes" are used primarily for ambient temperature testing, so they are called test tubes, or test-tubes. Taking a test-tube in and out is for decreasing the heat flow to prevent violent overheating and the burst of boiling liquid shooting out of the tube.
Solubility of Amides - Chemistry Stack Exchange
2020年7月10日 · Amides generally have higher boiling points and melting points than related alcohols and acids - because of their unique ability to be internal hydrogen donors and acceptors. This donor-acceptor capability makes their solid state more stable and less able to be solvated to a greater degree in water.
Why do branched chain compounds have lower boiling points …
2013年11月15日 · Consequently, the boiling points of the branched chain alkanes are less than the straight chain isomers. The above excerpt from my book, mentions clearly that branching makes the molecule more compact and thereby decreases the surface area. Even for isomeric alkyl halides, the boiling points decrease with branching.
Boiling and melting point of trans- and cis-but-2-ene
2015年3月4日 · Boiling point depends upon intermolecular interactions which over here is more in cis due to its net dipole moment . The dipole moment enables electronic interactions which hold molecules together . This shows some general factors of boiling point . Also the below link to the google book covers the structural aspect of a molecule towards b.p on ...
How to determine the boiling point of substances? [closed]
2019年4月6日 · This leads us to the conclusion that the mass of the molecule is proportional to the boiling point. Branches. In alkanes (consisting of $\ce{C}$ and $\ce{H}$ only), generally a straight chain alkane has a higher boiling point than similar branched alkanes due to the surface area between two adjacent molecules. This would be harder if the alkane ...