Balance the following oxidation-reduction reaction and indicate which atoms have undergone oxidation and reduction. Cu + HNO3 > Cu(NO3)2 + NO2 + H2O

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.