What pressure (in atmospheres) is required to contain 0.023 moles of nitrogen gas in a 4.2 L container at a temperature of 20°C?

It is a mixture. simply put, a compound must be pure, that is, of only one chemical structure and composition. a mixture is made of different chemical substances (i.e. elements, molecules, compounds) that are not chemically bonded to each other, but instead physically grouped together, as in the case of gasoline (a homogeneous solution).

I'm pretty sure its c

The answer is:   [d]:   "ultraviolet" {"  uv  "} .