Asample composed only of atoms having the same atomic number is classified as: 1. a compound 2. a solution 3. an element 4. an isomer

6. using 3 – 4 sentences explain (in your own words) why water expands when it freezes? 7. using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. use 3 – 4 sentences in your explanation.