Where did the halite crystals form the largest structures, on the string or along the side or top of the container?

Yes i think so not 100 percent sure though

Ibelieve y y even though i've only taken chemistry for one year

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).