Hey :)
This time the answer is quantitive because the mentions numbers
Hope this helps!
Answer : The energy required to melt 58.3 g of solid n-butane is, 4.66 kJ
Explanation :
First we have to calculate the moles of n-butane.

Given:
Molar mass of n-butane = 58.12 g/mole
Mass of n-butane = 58.3 g
Now put all the given values in the above expression, we get:

Now we have to calculate the energy required.

where,
Q = energy required
= enthalpy of fusion of solid n-butane = 4.66 kJ/mol
n = moles = 1.00 mol
Now put all the given values in the above expression, we get:

Thus, the energy required to melt 58.3 g of solid n-butane is, 4.66 kJ
Answer:
95.3g
Explanation:
Given parameters:
Mass of water = 540g
Percentage by mass of solution = 15%
Unknown:
Mass of sucrose = ?
Solution;
To solve this problem, we must understand that a solution is made up of solute dissolved in a solvent. A solute is the solid dissolved in another. The solvent is the is dissolving medium;
Percentage by mass of solute in solution = 
Mass of solution = mass of water + Mass of sucrose = 540 + M
where M is the mass of sucrose;
therefore;
= 15
Solving for M gives 95.3g
Mass of sucrose is 95.3g
Simple!
Atomic number= number of protons AND number of electrons (in an atom)
Mass number= number of neutrons