1. The problem statement, all variables and given/known data Classify each of the following as a pure substance, solution, or heterogeneous mixture: a) blood b) dry ice c) krypton gas d) a rusty nail e) table salt f) glass of lemonade Justify your answers. 2. Relevant equations No equations obviously... 3. The attempt at a solution Here's what I figure...but I'm not sure!!! a) blood - no idea... b) dry ice - pure substance (why???) c) krypton gas - pure substance (single element) d) rusty nail - heterogeneous mixture (rust is produced by oxidizing the iron) e) table salt - solution (homogeneous mixture of Na and Cl atoms) f) glass of lemonade - solution?? (I'm not sure because my book said milk is heterogeneous but coffee is a solution) Yeah...so if you know, help me out! And if my justifications aren't right, please let me know that too :) Thanks to all.