Answers:
1) <span>Breaking Solvent-Solvent Attractions is an Endothermic Process.
2) </span><span>Breaking Solute-Solute Attractions is an Endothermic Process.
3) </span><span>Forming Solute-Solvent Attractions is an Exothermic Process.
Explanation:
When a solute is dissolved in solvent it either releases heat or absorbs heat depending upon the the interactions broken and interactions formed. At first, the solvent solvent interactions are broken , this process requires heat which is provided either from external source or is provided by the forming of solute solvent bond forming process which is exothermic.
When the solvent molecules get apart the solute particles enter to form interactions with elimination of heat. So, if the heat required to break solvent solvent interactions is greater than the heat provided by solute solvent interactions formation then the solute will not dissolve at room temperature and vice versa.</span>
Answer:

Explanation:
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In this case, according to the given information, it turns out possible for us to calculate the required new volume by using the Charles' law as a directly proportional relationship between temperature and volume:

In such a way, we solve for V2 and plug in V1, T1 and T2 to obtain:

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The balanced equation for the reaction is as follows
Na₂CO₃ + 2HCl --> 2NaCl + CO₂ + H₂O
stoichiometry of Na₂CO₃ to HCl is 1:2
number of Na₂CO₃ moles reacted = molarity x volume
number of Na₂CO₃ moles = 0.100 mol/L x 0.750 L = 0.0750 mol
according to molar ratio of 1:2
1 mol of Na₂CO₃ reacts with 2 mol of HCl
then 0.0750 mol of Na₂CO₃ mol reacts with - 2 x 0.0750 = 0.150 mol
molarity of given HCl solution is 1.00 mol/L
molarity is defined as the number of moles of solute in 1 L of solution
there are 1.00 mol in 1 L of solution
therefore there are 0.150 mol in - 0.150 mol / 1.00 mol/L = 0.150 L
volume of HCl required is 0.150 L
<span>the following element that is most reactive </span>would be Fluorine