Question 12: The density of platinum (Pt) is 21.45 g/cm³. Assume that Pt atoms are cubes packed together with no empty space between them. Determine the edge length of one "cubic Pt atom" in pm. 4

A materials engineer has filed for a patent for a new alloy to be used in golf club heads. The composition by mass ranges from 25 to 31% manganese, 6.3 to 7.8% aluminum, 0.65 to 0.85% carbon, and 5.5 to 9.0% chromium, with the remainder being iron. What are the maximum and minimum percentages of iron possible in this alloy? Use Figure 2.12 to snake a prediction about how the density of this alloy would compare with that of iron; justify your prediction.

If we classify substances as ionic, molecular, macromolecular, or metallic, in which if any categories are all the members a. soluble in water? b. electrical conductors in the melt? c. insoluble in all common solvents? d. solids at room temperature?

On October 21, 1982, the Bureau of the Mint changed the composition of pennies (see Exercise 120). Instead of an alloy of 95% Cu and 5% Zn by mass, a core of 99.2% Zn and 0.8% Cu with a thin shell of copper was adopted. The overall composition of the new penny was 97.6% Zn and 2.4% Cu by mass. Does this account for the difference in mass among die pennies in Exercise 120? Assume the volume of the individual metals that make up each penny can be added together to give the overall volume of the penny, and assume each penny is the same size. (Density of Cu = 8.96 g/cm3; density of Zn = 7.14 g/cm3).