Which of the following compounds has a high melting point and boiling point?

One similarity and one difference between an element and a mixture of elements

Substance a is a nonpolar liquid and has only dispersion forces among its constituent particles. substance b is also a nonpolar liquid and has about the same magnitude of dispersion forces among its constituent particles. when substance a and b are combined, they spontaneously mix.

The term gas is limited to those substances that exist in the gaseous state at