Which is an indication that a chemical change to a substance has occurred?   a. it changes shape b. new substances are formed c. energy is used or given d. both b and c

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.

Identify the lewis acid in this balanced equation: ag+ + 2nh3 -> ag(nh3)2+a. ag+b. nh3c. ag(nh3)2+

Which polymers are most closely related? a. protein and nucleic acids b. cellulose and starch c. nucleic acids and starch d. nucleic acids and cellulose