Answer:
The average atomic mass is closer to Si- 28 because this isotope is present in more percentage in the sample.
Explanation:
Given data:
Atomic mass of silicon= ?
Percent abundance of Si-28 = 92.21%
Atomic mass of Si-28 = 27.98 amu
Percent abundance of Si-29 = 4.70%
Atomic mass of Si-29 = 28.98 amu
Percent abundance of Si-30 = 3.09%
Atomic mass of Si-30 = 29.97 amu
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)+(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass = (92.21×27.98)+(4.70×28.98)+(3.09×29.97) /100
Average atomic mass = 2580.04 +136.21+92.61 / 100
Average atomic mass = 2808.86 / 100
Average atomic mass = 28.08amu.
The average atomic mass is closer to Si- 28 because this isotope is present in more percentage in the sample.
Answer:
Benzaldehyde is less electrophilic than acetaldehyde
Explanation:
Electrophilicity of carbonyl carbon depends on it's positive charge density.
In benzaldehyde, phenyl group can act as an electron donating group towards carbonyl group due to it's electron donating resonating effect.
In acetaldehyde, methyl group can act as an electron donating group towards carbonyl group due to it's electron donating inductive effect.
We know that resonating effect are more stronger than inductive effect.
Henece, it is expected that positive charge density on carbonyl carbon is much lower in benzaldehyde than acetaldehyde.
So, benzaldehyde is less electrophilic than acetaldehyde.
Resonating effect of phenyl group has been shown below.
It shall be A.<span>Oppositely charged ions attract</span>