The half-life of 59Fe is approximately 45 days. How many milligrams of a 6.4 mg sample will remain after 180 days?

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.

Once similarity and one difference between a mixture of elements and a mixture of compounds

#20 which type of bond is formed when bases pair in dna? ionic bond covalent bond coordinate bond hydrogen bond