<span>This is a physical property. Physical properties involve changes of phase, or state of matter, of which melting is an example. Melting involves a change from a solid state to a liquid state. The internal energy of the solid increases, usually by applying heat, which increases the temperature to the melting point of the substance.</span>
Since this process involves a matter-state change from solid to liquid, melting is occurring.
Ionic compounds have very strong intermolecular 'bonds': this is because it is formed by a metal atom donating one or more electrons to a non-metal atom in order to result in complete valence shells, with the effect that opposite ions are formed (opposites attract). Hence a large input of energy is needed to overcome these 'bonds' and form a liquid from the giant solid ionic lattice - therefore ionic compounds have high melting and boiling points.
Conversely a covalent bond occurs between two non-metal atoms - unlike ionic compounds which form giant ionic structures, covalent bonds are used to form molecules. These only have weak intermolecular forces, which need a small energy input to overcome: therefore the melting and boiling points will be much lower.
Considering that the compound has been taken from the freezer, which is 0 degrees celcius or lower, the state change has occurred at a low temperature. This makes it extremely likely that the compound is covalent.
In conclusion, the correct answer is d.
VSEPR is an acronym which stands for Valence Shell Electron Pair Repulsion. The theory is most commonly used as basis for establishing the shapes of the substances.
CF4, as can be seen, has only one carbon atom and four fluorine atoms. The most preferred shape of the chemical is therefore, tetrahedral.
11.2L x 1mol/22.4L= 0.5 mol