Everyone of us knows that there was an Intense Volcanic activity for the first billion year of Earth. Due to the circumstances, the amount of gases in our atmosphere was very unsupportable for existence of life(Very similar like the atmosphere of Mars & Venus of today).
Amount of Carbon dioxide was most abundant whereas oxygen was very little. Then, the changes which affect the proportion of gases were:
1) For Increasing Oxygen. - The only and most important source of increasing oxygen was the "Photosynthesis by Plants".
2) For decreasing Carbon dioxide. - (i) Absorbed by plants in order to do the process of photosynthesis.
(ii) Most of the CO2 dissolved in Oceans and many locked in <span>sedimentary rocks, such as limestone, and in fossil fuels.
In that way, Our Atmosphere evolved,and now we're able to survive (If we care about our environment)
Hope this helps!</span>
Answer: The small intestine breaks down the food by using enzymes that were released from the pancreas and use the bile from the liver. The bile helps with the digestion of fat as well eliminating waste from the blood.
Explanation:
I will state the electronegativities of each element.
Ca = 1.00
F = 3.98
H = 2.20
P = 2.19
Na = 0.93
The highest electronegative element is F (Fluorine).
Answer:
The main competing reaction when a primary alkyl halide is treated with alcoholic potassium hydroxide is SN2 substitution.
Explanation:
The relative percentage of products of the reaction between an alkyl halide and alcoholic potassium hydroxide generally depends on the structure of the primary alkylhalide. The attacking nucleophile/base in this reaction is the alkoxide ion. Substitution by SN2 mechanism is a major competing reaction in the elimination reaction intended.
A more branched alkyl halide will yield an alkene product due to steric hindrance, similarly, a good nucleophile such as the alkoxide ion may favour SN2 substitution over the intended elimination (E2) reaction.
Both SN2 and E2 are concerted reaction mechanisms. They do not depend on the formation of a carbocation intermediate. Primary alkyl halides generally experience less steric hindrance in the transition state and do not form stable carbocations hence they cannot undergo E1 or SN1 reactions.
SN2 substitution cannot occur in a tertiary alkyl halides because the stability of tertiary carbocations favours the formation of a carbocation intermediate. The formation of this carbocation intermediate will lead to an SN1 or E1 mechanism. SN2 reactions is never observed for a tertiary alkyl halide due to steric crowding of the transition state. Also, with strong bases such as the alkoxide ion, elimination becomes the main reaction of tertiary alkyl halides.
