I would think the last one about the ozone layer
Answer:
It is always less than the theoretical yield
Explanation:
For many chemical reactions, the actual yield is usually less than the theoretical yield. This is due to possible loss in the process or inefficiency of the chemical reaction.
At divergent boundaries, plates separate, forming a narrow rift valley. Here, geysers spurt super-heated water, and magma, or molten rock, rises from the mantle and solidifies into basalt, forming new crust. Thus, at divergent boundaries, oceanic crust is created.
It is not directly over a flame because it depends on the substance you might not want to heat it too much.you never know what could happen
Each of the Nitrogen atoms has 2 non bonded valence electrons, meaning that there are 4 pairs total.
