No, it's not. Pastel chalk or soft pastel is easier to blend and draw with because it is softer, hence the name, soft pastel. Soft pastels are made of ground pigments, gum tragacanth, and a filler....
chalk is a very pure form of limestone made of calcite. i think >:P
By evaporation.
YEP!
Leverage. With a long piece of chalk you have more to grasp, enabling you to bend it until it snaps.