Answer:
To fulfill octet of B atom in borane, nucleophilic attack by pi electrons of alkene takes place with electrophilic B center in borane.
Explanation:
In Borane (
), B atom has energetically vacant 2p orbital and thereby octet is incomplete.Therefore B center in borane act as an electrophilic center.
In alkene, pi bonding electrons are loosely bound together due to side on overlap of two constituent p-orbitals. Hence this pi bond can be easily broken. Alternatively, we can say that pi bond in alkene act as a potential nucleophile.
The first step of hydroboration occurs in a concerted manner where pi electrons of alkene first attack vacant 2p orbital of B in borane to fulfill it's octet (represented by an arrow drawn from alkene to B atom) and forms a 4 memebered cyclic intermediate. Simulaneously, a B-H bond in borane is donated to alkene through 3c-2e bond (3 center-2 electron bond).
Full mechanism has been shown below.
4. It is an endothermic process. The body of someone taking a shower would be absorbing heat from the environment, another example of this would be cooking an egg
5. Ice melting is endothermic. The ice is absorbing heat from the environment, water freezing would be an exothermic reaction as it is transferring heat into the environment
6 however i do not have an answer for. I may just be a little dense but I'm not entirely sure what it is asking when it asks what the system is.
Answer:anions with least precipitates are anions of salt produce by a strong acid and strong base e.g KCL,Na2SO4,
Explanation: salts produce from strong acid such as HCL and a strong base such as KOH are extremely soluble and hence produce little or no precipitate when dissolved in water .meaning the salt are highly soluble , most group1 elements form salts that are highly soluble and hardly precipitates e.g Na(sodium) pottasium(K) ,lithium(Li)salts.they are called alkaline metals.
B) exception to the rules are hydrogen and Rubidium.hydrogen because it occurs basically as a gas and forms H^+ which tend to form a hydrogen bond while rubidium is a heavy metal forming insoluble salt
Answer:
The climate was very hot and became colder in later time periods.
Answer:
------ At point A, the skateboarder’s energy is all potential since she is high up (PE = mgh), and gravity has the potential to pull her down. She isn't moving, so she doesn't have velocity. Therefore, she doesn't have kinetic energy. At point B, she is moving the fastest during her ride and is as close to the ground as the ramp allows. Thus, her potential energy has been turned into kinetic energy due to her velocity and lack of height. At point C, if she comes to a stop on the other side of the half-pipe, her kinetic energy has been turned back into potential energy since she is high up again.
------- Eventually, the friction between the wheels and the ground will cause the skateboard to stop. Each time she goes back and forth, she will lose some of her initial energy from her drop-in, as long as she doesn't push off the sides at all.
Explanation:
