Answer:
Those two horizontal lines.
Explanation:
Hello there!
In this case, when focusing on these heating curves, it is important to say they tend to have two constant-temperature sections and three variable-temperature sections. Thus, from lower to higher temperature, the first constant-temperature section corresponds to melting and the second one vaporization, whereas the three variable-temperature sections correspond to the heating of the solid until melting, the liquid until vaporization and the gas until the critical point.
In such a way, we infer that the boxes referred to constant temperature are referred to a gain in potential energy, that is, the two horizontal lines.
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All of the above will be affected by air resistance, but the most obvious will be the balloon or leaf.
Hope it helps somewhat!
Answer:
Take approx 41.7 mL of 12-M HCl in a 1.00-L flask and fill the rest of the volume with distilled water.
Explanation:
Hello,
In this case, for the dilution process from concentrated 12-M hydrochloric acid to 1.00 L of the diluted 0.50M hydrochloric acid, the volume of concentrated HCl you must take is computed by considering that the moles remain constant for all dilution processes as shown below:

Which can also be written in terms of concentrations and volumes:

Thus, solving for the initial volume or aliquot that must be taken from the 12-M HCl, we obtain:

It means that you must take approx 41.7 mL of 12-M HCl in a 1.00-L flask and fill the rest of the volume with distilled water for such preparation.
Best regards.
You can calculate the gram formula mass of this compound by adding the atomic mass of every element in this compound according to the periodic table of elements.
Answer : The amount of heat released, 45.89 KJ
Solution :
Process involved in the calculation of heat released :

Now we have to calculate the amount of heat released.
where,
Q = amount of heat released = ?
m = mass of water = 27 g
= specific heat of liquid water = 4.184 J/gk
= specific heat of solid water = 2.093 J/gk
= enthalpy change for fusion = 40.7 KJ/mole = 40700 J/mole
conversion :
Now put all the given values in the above expression, we get
(1 KJ = 1000 J)
Therefore, the amount of heat released, 45.89 KJ