Answer:
Cl2
Explanation:
Cl2 is a covalent molecule because it contains 2 non-metal elements.
It is non-polar because both elements have the same level of electrostatic attraction (remember that electrostatic attraction is the tendency to steel an electron from an element with lower a lower electrostatic force)
In Cl2 since there are only 2 molecules that are the exact same there is no overall dipole (which means that one end of the molecule is slightly positive or negative charge)
If the molecule replaced one Cl or something else then it would be non-polar since one element will be more electrostatic than the other and one region of the molecule will have a slightly positive or negative charge, unless the molecule is symmetrical like CH4.
For CH4 (methane) if you drew this as a lewis structure the Carbon would be surrounded by 4 hydrogen atoms meaning the overall dipole will be cancelled out since the molecule is symmetrical.
You may not understand the last part but just know that:
If there are 2 of the same atoms in the molecule (Cl2) then it is non-polar
If there are 2 non-metals then the bond is covalent
Water is always polar
The answer is; D
An increase in carbon (usually carbon dioxide and methane) in the atmosphere increases the greenhouse effect on the surface of the earth. This is because carbon dioxide and methane are greenhouse gases that warm up the planet ( causing climate change) by trapping UV light from the sun. The ice sheets in the polar regions begin to melt due to a warming planet and the ocean levels rise. This causes flooding in the coastal regions and the higher tidal ranges erode the beaches.
I don't know what the options were but a material that is very likely going to be challenging to recognize under a microscope as a mixture is a homogeneous mixture. A homogenous mixture is uniform and thus hard to recognize as a mixture. An example is water!
Answer:
D
the angles wich light is coming into the medium are not the same for all wavelengths (colors, at least in the visible spectrum). same for outgoing light.
the same it true for any transparent barrier between two different materials, like air and water.