Bond angle of ch4 = 109.5
A solution is a mixture (solvent + solute) of 2 or more elements, for example chocolate milk.
A solvent is the base of the solution which dissovles a solute, for example milk.
A solute is what is dossolved by the solvent, for example chocolate powder.
This is because temperatures determine the kinetic energy of molecules of a substance, At lower temperatures the molecules have low kinetic energy hence the distance between molecules is not as large as when the kinetic energy is higher (because the molecules bombard less and with less kinetic energy). This means the substance can pack more molecules per volume at lower temperatures. The more the molecules per volume the higher the density.