Answer: <span>The molecules of a substance which must have the
<u>a</u></span>
<u>bility to move past one another</u> are said to be flexible.
Explanation: Those substances are said to be flexible which can be
bent without breaking. There are many substances which are
hard in nature but still can be bent. The hardness of such materials is due to
strong interactions between the molecules and the flexibility comes due to their
amorphous backbone. Therefore, greater the
crystalline level of macromolecules lesser is the flexibility and greater the amorphous character greater is the flexibility and vice versa. Also, the flexibility of polymers is increased by adding
plastisizers in it. Plastisizers make the hard polymers flexible by breaking the crosslinkers and enabling the macromolecules to move past one another.
Answer:
d) An atom of arsenic has one more valence electron and more electron shells than an atom of silicon, so the conductivity increases because the arsenic atom loses the electron.
Explanation:
This is an example of a n-type semiconductor. The additional electron introduced to the 'grid' of silicon atoms causes an increase in the conductivity of the silicon. This additional electron is introduced as arsenic loses its extra electron.
There are FOUR electrons in the 3p sub-level of sulfur....
Answer : The heat of the reaction is -221.6 kJ
Explanation :
Heat released by the reaction = Heat absorbed by the calorimeter


where,
= heat released by the reaction = ?
= heat absorbed by the calorimeter
= specific heat of calorimeter = 
= change in temperature = 
Now put all the given values in the above formula, we get:


As, 
So, 
Thus, the heat of the reaction is -221.6 kJ