The answer is b. hot spots
(3) The concen<span>tration of the solution remains constant.</span>
Answer: 1-Propene has
eight sigma bonds and
one pi bond.
Explanation: The lewis structure of 1-Propene is shown below. All sigma bonds are highlighted by
blue color and the pi bond is highlighted by
red color.
Carbon having four unpaired electrons in its excited state can form four covalent (sigma bonds) bonds. In given structure the orbitals containing unpaired electron in sp³ hybridized C undergo head to head overlap with three hydrogen atoms having single unpaired electron and orbital of other sp² hybridized carbon in same fashion. So, four sigma bonds are formed by sp³ hybridized carbon atom.
The doubly bonded carbon atoms also form sigma bond but two unpaired electrons of these two carbons undergo the formation of pi bond. This pi bond forms when the orbitals overlap along the plane perpendicular to the existing sigma bond resulting in the formation of single pi bond.
Answer:
Space junk is travelling so fast that a collision with an astronaut or a spacecraft could be disastrous.
Explanation:
Space junk orbits the Earth at speeds of about 28 000 km/h.
That's so fast that even an orbiting fleck of paint has enough kinetic energy to cause impact craters on the surface of a spacecraft. They are even more dangerous to an astronaut on a space walk.
Much of the space debris is larger and more dangerous than a fleck of paint.
One rough estimate of the amount of space debris is
<em> </em><u>Size</u><em> </em> <u>Number of objects</u>
< 1 cm 200 000 000
1 cm to 10 cm 700 000
> 10 cm 30 000
Satellites, etc. 18 000
The chances of collision are small, but any collision can be disastrous.