Ce - 141; 3.2mu * C * i after 130 The half - life for the radioactive decay of is 3.9 Ci after 195 d have elapsed , what was the initial activity in microcuries , of the sample ?

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.