To determine the mass of the sample, first find the volume difference after and before the aluminum was placed, the volume change is equal to the volume of the submerged object, in this case aluminum.
Then knowing volume of aluminum and the density of it, we can solve for the mass.
D = m/v
Dv = m
2.7 g/ml • 8 ml = 21.6 grams.
One of the causes of polarity is the unequal forces of the dipole forces due to differences in electronegativity. The more electronegative molecule tend to attract electrons, hence the polarity arrows point towards it. The electronegativity of Phosphorus and Fluorine is 2.19 and 3.98, respectively. Thus, it points outward towards the fluorine atoms.
Lower
Melting points of molecular solids are lower than melting points of ionic compounds
