Cohesion holds hydrogen bonds together to create surface tension on water. Since water is attracted to other molecules, adhesive forces pull the water toward other molecules.
Answer:
A catalytic converter changes nitrogen dioxide to nitrogen gas and oxygen gas is a chemical change.
Explanation:
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In this case, since physical changes do not modify the molecular composition and structure of the material undergoing it whereas the chemical change does, for catalytic converters we should know they promote chemical reaction in which the composition is changed; for instance, for the given example, the following chemical reaction is the evidence:
As you can see, nitrogen and oxygen are no longer bonded but separated by themselves, therefore, this is a chemical change.
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Answer:
In a semiconductor, the bonding molecular orbitals that contain electrons are referred to as the valence band, while the antibonding orbitals that are completely empty are referred to as the conduction band.
The conduction band occupies a higher energy level than the valence band. The band gap is what separates the two orbitals.
Answer:
Density= 1.7g/dm3
Explanation:
Applying
P×M= D×R×T
P= 2atm, Mm= 28, D=? R= 0.082, T= 400K
2×28= D×0.082×400
D= (2×28)/(0.082×400)
D= 1.7g/dm3
An extra shell, which means further distance between those electrons in the valence shell and the nucleus. Ionisation energy refers to the energy required to remove valence electrons. There will be more energy required if the valence electrons are closer to the nucleus that have a positive charge, because of more attraction. If there is an extra shell, there is further distance, less attraction and hence less energy required.
