As a diffusion expert you are to calculate the thickness of Ag required to maintain at least a 99% Ag alloy on the surface of Cu for 5 years. The most accurate data you can locate is a study of D for Ag in Cu between 750 and 1050°C. Extrapolating these data to 150°C, you find that a 1 micrometer layer of Ag will last for 150 years. A laboratory test shows that a 1 micrometer silver layer completely dissolves in a sample over a weekend at 150°C. Why might the calculation of the rate at 150°C be invalid?

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. 8. when a 2.5 mol of sugar (c12h22o11) are added to a certain amount of water the boiling point is raised by 1 celsius degree. if 2.5 mol of aluminum nitrate is added to the same amount of water, by how much will the boiling point be changed? show all calculations leading to your answer or use 3 – 4 sentences to explain your answer. 9. if 5.40 kcal of heat is added to 1.00 kg of water at 100⁰c, how much steam at 100⁰c is produced? show all calculations leading to an answer. 10. the freezing of water at 0⁰c can be represented as follows: h2o (l) ↔ h2o(s) the density of liquid water is 1.00 g/cm3. the density of ice is 0.92 g/cm3. in 3 – 4 sentences explain why applying pressure causes ice to melt.