Worksheet 1 Spring E-344 Tuesday 25 March, 2008 Please use whatever reasonable resource available to you in class to address the following questions. You may use your notes, books, the web, as well as your colleagues in class. I encourage the latter. Try not to be too disruptive in our crowded classroom. Please try to execute this work in the spirit that it is intended: namely, to help each of you learn some of the basic issues associated with phase diagrams. This is a topic we will begin studying in lecture soon. The relevant portion of Callister is the beginning sections of Chapter 9. By the end of the class period, please hand in your solution sheet. Include your name and your 4 digit ID number. NOTE – We will NOT have class on Thursday 3/27. I encourage you to use this time to study for Test 2 on Thursday 3 April. Name: ________________________ ID#: ________________________ 1. Define the term “solid solution.” 2. Define the term "solubility limit." 3. Figure 9.1 in Callister (reproduced in the adejacent figure) shows a portion of the water-sugar binary phase diagram. Suppose you are given a glass containing 100 grams of a water-sugar solution. The solution is at room temperature (20 oC). The concentration of sugar in the mixture is the maximum that can completely dissolve in the water. (a) According to this diagram, how many grams of sugar are in the glass? (b) What will happen to the solution if the temperature is lowered from 20 oC to 15 oC? (c) Does the maximum solubility of sugar of in water increase, decrease, or stay the same as temperature is increased? 4. The pressure-temperature phase diagram for pure water is given by figure 9.2 in Callister and is reproduced above. Use this diagram to explain why a thin layer of liquid water forms between the blade of an ice skater's skate and the solid ice below. Assume the ice at the skating rink is held at -2 oC. 5. Callister Concept Check 9.2. A copper-nickel alloy of composition 70 wt% Ni 30 wt% Cu is slowly heated from a temperature of 1300 oC. The copper-nickel isomorphous phase diagram is given as Callister figure 9.3 and is reproduced below. (a) At what temperature does the first liquid phase form? (b) What is the composition of this liquid phase? (c) At what temperature does complete melting of the alloy occur? (d) What is the composition of the last solid remaining prior to complete melting?