Explain how the direction of the arrow in the bond dipole symbol ( ) relates to the elec-tron density and the partial charges.

The complete question is shown in the image attached

See explanation

Explanation:

In a molecule, the direction of the dipole moment also shows the direction of the shift in electron density. Let me give you an instance. In HCl, the dipole points towards the chlorine atom. This implies that the bond is polar and the chlorine atom accommodates the greater share of the electron density of the H-Cl bond. The negative partial charge rests on the more electronegative atom (chlorine in this case) while the partial positive charge rests on the more electropositive atom(hydrogen in this case). Recall that the difference in electron density between the two atoms creates this polarity.

Having said that much, let me come to the issue of electronegativity and bond polarity. The polarity of bonds depends on the electronegativity difference between atoms. I have just established that the H-Cl bond is polar owing to the difference in electronegativity between hydrogen and chlorine. If I replace the chlorine atom in the molecule with another hydrogen atom, the molecule is no longer polar because the difference in electronegativity of a H-H bond is zero.

Lastly, let me talk about electronegativity difference and bond character. The magnitude of electronegativity difference between atoms determines the bond character. If the electronegativity difference between bonding atoms is;

less than 0.4, the bond is a pure covalent bond

between 0.4 - 1.8, the bond is a polar covalent bond

greater than 1.8, the bond is a pure ionic bond  

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%

lol idk man i guess u gotta ask bill nye the science guy