Since you didn't have any extra information about the question I'll be presenting an example from my own textbooks that I've used.
An example of a direct observation is listening to a cricket chirp at night, and counting the number of chirps per minute.
Direct Observation is where the evaulator watches the subject in their usual habitat without disrupting or altering it.
Answer:
Molecular oxygen and Hydrogen fluoride.
Explanation:
Definition:
Hydrogen bonding:
It is a type of dipole-dipole attraction between the hydrogen atom and more electronegative atoms.
In hydrogen bonding mostly the highly electronegative atoms are fluorine, nitrogen and oxygen.
Explanation:
In given compound such as methane CH₄ the electronegativity of carbon is 2.55 while that of hydrogen is 2.2 so there is smaller electronegativity difference that's why it can not form hydrogen bond.
In case of molecular oxygen the electronegativite atom oxygen is present. It can form hydrogen bonds with water. its electronegativity is 3.44.
In case of hydrogen fluoride the electronegativity atom fluorine is present. It will form hydrogen bonds with water. Its electronegativity is 3.98. So it is more likely to take part in hydrogen bonding.
Answer:
No, because sulfur does not typically form negative ions or oxidation states less than 2−. The binary compound formed by sulfur and sodium is Na2S
Explanation:
Sulphur is a member of group 16. The oxidation states expected for sulphur in group 16 are -1, -2, +1, +2,+3,+4,+5 or +6. The elements of group 16 usually form negative ions with oxidation number of -2. They do not typically form negative ions with oxidation state less than -2.
The implication of this is that we actually do not expect the existence of a compound in which sulphur forms an S^4- anion. In reality, such an anion does not exist. Rather a binary compound of sulphur and sodium will have the formula Na2S because it contains the S^2- anion.
Answer:
This would affect the communities that use solar energy greatly, in a negative way.
Explanation:
If the moon were twice its size, and cast a larger shadow on Earth, the shadow would black out the earth to an almost night time, during the day. We would have a 24+ hour night, and communities relying on nothing but solar energy would be out of power until the sun was out again.
