Question

1. Predict which of the following liquids has greatersurface tension: ethanol (C2H5OH) or dimethyl ether (Ch3OCH3).

2. Metallic iron crystallizes in a cubic lattice. The unit celledge length is 287 pm. The density of iron is 7.87 g/cm^3. How manyiron atoms are within a unit cell?

3. A face-centered cubic cell contains 8 X atoms at the cornersof the cell and 6 Y atoms at the faces. What is the empiricalformula of the solid?

4. The distance between layers in a NaCl crystal is 282 pm. Xrays are diffracted from these layers at an angle of 23.0(degree).Assuming that n = 1, calculate the wavelength of the X rays innm.

5. How much heat in (kJ) is needed to convert 866 g of ice at -10 (degree)C to steam at 126(degree)C? (The specific heats of iceand steam are 2.03 J/g *(degree)C and 1.99 J/g* (degree)C,respectively.)

6. The molar heats of fusion and sublimation of molecular iodineare 15.27 kJ/mol and 62.30 kJ/mol, respectively. Estimate the molarheat of vaporization of liquid iodine.

7. The following compounds, listed with their boiling points,are liquid at -10(degree)C: butane,-0.5(degree)C; ethanol, 78.3(degree)C; toluene, 110.6(degree)C. At -10(degree)C, which of theseliquids would you expect to have the highest vapor pressure? Whichthe lowest? Eplain.

8. Vapor pressure measurements at several different temperaturesare shown below for mercury. Determine graphically the molar heatof vaporization for mercury.

t(degreeC) 200 250 300 320 340

P(mmHg) 17.3 74.4 246.8 376.3 557.9

9. The vapor pressure of benzene, C6H6, is40.1 mmHgat 7.6(degree)C. What is its vapor pressure at 60.6 (degree)C? Themolar heat of vaporization of benzene is 31.0 kJ/mol.

10. At -35(degree)C, liquid HI has a higher vaporpressure than liquid HF. Explain.

11. Melamine forms a precipitate by hydrogen bonding withcyanuric acid (C3H3N3O3), another contaminant present. Theresulting stomelike particles caused severe kidney damage in manybabies. Draw the hydrogen-bonded complex formed from these twomolecules. Melamine and Cyanuric acid.

12. A sample of limestone (CaCO3) is heated in a closed vesseluntil it is partially decomposed. Write an equation for thereaction and state how many phases are present.