Answer:
The correct answer is:
<em>(1) It is important that the sample is dissolved in just enough hot solvent. </em>
Explanation:
The process of recrystallization is important to eliminate the impurities and to obtain better crystals of the solid. The solvent used to perform the recrystallization must have a high dissolution power of the substance to be recrystallized and a low dissolution power of the impurities. This is in order to eliminate most impurities. Furthermore, <em>It is important that the sample is dissolved in just enough hot solvent </em>because this should be easy to remove after the recrystallization and the crystal should form easily when the solution cools. Also, it is better to add the hot solvent to solubilize the crystals and keep the impurities insoluble, instead of adding the cold solvent and heating the solution. Additionally, the process of cooling the solution must be done slowly to obtain large and fewer crystals. A fast ice-cooling will form smaller crystals.
A standard drink of beer is 12 ounces
Answer: The molar enthalpy change is 73.04 kJ/mol
Explanation:
moles of HCl= 
As NaOH is in excess 0.0415 moles of HCl reacts with 0.0415 moles of NaOH.
volume of water = 100.0 ml + 50.0 ml = 150.0 ml
density of water = 1.0 g/ml
mass of water = 
q = heat released
m = mass = 150.0 g
c = specific heat = 
= change in temperature = 
Thus 0.0415 mol of HCl produces heat = 3031.3 J
1 mol of HCL produces heat = 
Thus molar enthalpy change is 73.04 kJ/mol
