Answer:
I am not sure if this is the answer but maybe oil?
I'll go through them one by one
1) H-S
The electronegativity of Hydrgoen is 2.2, and sulphur is 2.58,
therefore the difference is 0.38 (2.58-2.2=0.38)
2) H-Cl
Hydrogen: 2.2, Chlorine: 3.16
therefore difference is 0.96
3) N-H
Nitrogen: 3.04, Hydrogen: 2.2
therefore difference is 0.84
4) C-H
Carbon: 2.55, hydrogen: 2.2
therefore difference is 0.35
so, the most apparent electronegativity is chlorine, but this could have been done without actually doing the maths. The trend of electronegativty increases across a period and increases up a period due to the strong affinity of the nucleus with bonding electrons. This does not include noble gases though, as they have no charge due to having complete valance shells. T<span>he most electronegative element is Fluorine (9), and the least electronegative element (besides noble gases) is Francium (87)</span>
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.
For a polar molecule<span>, your bonds will not cancel out. This means that in a </span>polar<span> bond, the electronegativity of the atoms will be different. For </span>nonpolar<span> bonds the electronegativity of the atoms will be equal. In a </span>polar<span> bond you will have an unequal sharing of electron pairs which causes a molecular dipole.</span>