P1: Trim: 8.375in × 10.875in

LWBK575-02-Stud-Ans LWW-Sinko-educational March 26, 2010 20:53

A N S W E R S T O P R A C T I C E P R O B L E M SF O R S T U D E N T U S E

CHAPTER 2: STATES OF MATTER

2–1 219 liters.

2–2 The volume of the bubble at the bottom of the tank is4.19 ×10−3 cm3. The radius of the bubble increasesfrom 0.1 cm to 0.11 cm as the bubble rises to thesurface.

2–3 161 g/mole.

2–4 (a) 64.1 g/mole; (b) the molecular weight should pro-vide a strong clue.

2–5 (a) 47.23 psi; gauge pressure = 32.5 psig;(b) 14.69594 lb (avoirdupois)/in.2 = 101,325 kg m−1

s−2 = 101,325 N m−2 = 101,325 Pa; (c) check withyour local service station attendant.

2–6 (a) 0.256 atm or 194.3 torr; (b) 0.254 atm or193.3 torr.

2–7 (a) 0.0177 kg; (b) 9.84 liter; (c) 9.64 liter.

2–8 55.2 mm Hg.

2–9 From the graph, the vapor pressure, P , is 43.7 torr;�HV = 10,282 cal/mole. Using linear regression, wefind �HV = 10,267 cal/mole and P = 43.9 mm. Theheat of vaporization, �HV, of ethyl alcohol given inthe CRC Handbook of Chemistry and Physics, 67thEd., is 9673.9 cal/mole.

2–10 Partial Answer: (a) Butane, −11.30◦C; propane,−50.73◦C; (c) Water boiling point is about 89◦C atthe mountain top.

2–11 (a) p′ = 329.3 torr; (b) �HV′ = 7112 cal/mole.

2–12 (a) �T = −0.470 K ; (b) �T = −0.468 K.

2–13 (a) Using equation (2–17), we obtain �T/�P =−0.041 K /atm; (b) 49.4◦C. If the temperature dur-ing processing were greater than 50◦C, form I mightchange to form II.

2–14 (a) 30 g; 105 g; (b) 9.00 g; 97.65 g.

2–15 (a) There is a single liquid phase up to 31% w/wof A present, at which point two liquids are formed(compositions are 31% w/w A and 78% w/w A). Asmore A is added, the amount of the second phase, B,decreases while that of the first phase A increases.When the system exceeds 78% w/w A at 25◦C thetwo phases disappear and the system again becomesone phase. (b) At 45◦C, we are above the region ofimmiscibility, and hence a single phase exists for allcombinations of A and B.

2–16 (a) 30% w/w A and 70% w/w B; 80% w/w A and20% w/w B. These are conjugate phases; (b) 40 g ofA and 10 of B g.

2–17 (a) 39◦C; (b) 15 g of B (to produce a system contain-ing 20% w/w A and 80% w/w B); (c) 40 g of A (toproduce a system containing 90% w/w A and 10% B).

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