A cold acetic acid solution is used to wash the residue of
the reagent in preparation of an aldol condensation product after vacuum
filtration. The main reason in washing
with the acetic acid rinse is to neutralize any sodium hydroxide.
Answer:
a) 
b) 
c) Compressing is easier
Explanation:
Given:
Expression of force:

where:



when the spring is stretched
when the spring is compressed
hence,

a)
From the work energy equivalence the work done is equal to the spring potential energy:
here the spring is stretched so, 
Now,
The spring constant at this instant:



Now work done:



b)
When compressing the spring by 0.05 m
we have, 
<u>The spring constant at this instant:</u>



Now work done:



c)
Since the work done in case of stretching the spring is greater in magnitude than the work done in compressing the spring through the same deflection. So, the compression of the spring is easier than its stretching.
Answer:
Terminal velocity of object = 12.58 m/s
Explanation:
We know that the terminal velocity is attained when drag force and gravitational force are of the same magnitude.
Gravitational force = mg = 80 * 9.8 = 784 N
Drag force = 
Equating both, we have

So v = 12.58 m/s or v = -15.58 m/s ( not possible)
So terminal velocity of object = 12.58 m/s
It will be a little bit less because of evaporation i learned that in third grade and your in high school that is sad