Topic: Bargg Equation

Transcription

1 1. Calculate the interplanar distance that has a second order reflection of 22.9 C for X-rays of wavelength of nm. a) nm b) nm c) nm d) 1.79 nm e) nm 2. The interplanar distance of a crystal is nm. At what angle will the second order reflections occur for X-rays of nm wavelength? a) 27.4 b) 20.5 c) 67.2 d) 35.6 e) Calculate the interplanardistance that has a second order reflection of 67.0 for X-rays of wavelength of nm. a) nm b) nm c) nm d) nm e) nm 4. Copper crystallizes in a face centered structure. The edge of the unit cell is 361 pm. What is the radius of the copper atom. a) 180 pm b) 156 pm c) 128 pm d) 162 pm e) 198 pm 5. Chromium crystallizes in a body centered structure. The edge of the unit cell is nm. What is the radius of the chromium atom. a) nm b) nm c) nm d) nm e) nm PHYSICAL CHEMISTRY by: SHAILENDRA KR. Classes at: - Meq. Approach SCIENCE TUTORIALS; Opp. Khuda Baksh Library, Ashok Rajpath, Patna PIN POINT STUDY CIRCLE; House No. 5A/65, Opp. Mahual Kothi, Alpana Market, Patna Topic: Bargg Equation 6. Sodium crystallizes in a body centered structure. The edge of the unit cell is 430 pm. What is the radius of the sodium atom. Page No.: 1

2 a) 175 pm b) 164 pm c) 186 pm d) 202 pm e) 152 pm 7. The number of atoms per unit cell in a face centered cubic structure is : a) 1 b) 4 c) 2 d) 6 e) 8 8. The number of atoms per unit cell in a simple cubic structure is : a) 2 b) 1 c) 4 d) 6 e) 8 9. The number of nearest neighbors in a simple cubic cell of identical atoms is : a) 4 b) 6 c) 8 d) 10 e) 12 e) 345 pm 10. Europium has an atomic radius of nm. The density of europium is g/cm 3. What is the crystal structure of europium? (Atomic weight: Eu = ). a) simple cubic b) body centered cubic d) face centered cubic 11. Lithium has an atomic radius of nm. The density of lithium is g/cm 3. What is the crystal structure of lithium? (Atomic weight: Li = 6.94). a) simple cubic b) body centered cubic d) face centered cubic 12. Chromium has an atomic radius of nm. The density of chromium is 7.19 g/cm 3. What is the crystal structure of chromium? (Atomic weight: Cr = 52.0). a) face centered cubic b) body centered cubic d) simple cubic 13. The density of platinum (face centered cubic cell) is g/cm 3 at 20 C. What is the length of an edge of a unit cell? (Atomic weight: Pt = 195.1). a) 392 pm b) 382 pm c) 349 pm d) 371 pm e) 360 pm 14. The density of Chromium (body centered cubic cell) is 7.19 g/cm 3 at 20 C. What is the length of an edge of a unit cell? (Atomic weight: Cr = 52.0). a) 289 pm b) 330 pm c) 315 pm d) 300 pm Page No.: 2

3 15. The density of iron (body centered cubic cell) is 7.87 g/cm 3 at 20 C. What is the length of an edge of a unit cell? (Atomic weight: Fe = 55.8). a) nm b) nm c) nm d) nm e) nm 16. The density of europium (body centered cubic cell) is 5.26 g/cm 3 at 20 C. What is the radius of the atom? (Atomic weight: Eu = ). a) 168 pm b) 198 pm c) 176 pm d) 185 pm e) 190 pm 17. The density of platinum (face centered cubic cell) is g/cm 3 at 20 C. What is the radius of the atom? (Atomic weight: Pt = 195.1). a) 149 pm b) 139 pm c) 160 pm d) 172 pm e) 188 pm 18. The density of lithium (body centered cubic cell) is g/cm 3 at 20 C. What is the radius of the atom? (Atomic weight: Li = 6.94). a) nm b) nm c) nm d) nm e) nm 19. A face centered unit cell of aluminum has a length of nm. Calculate the density of aluminum (g/cm 3 ). (Atomic weight: Al = 26.98). a) 2.70 b) 2.39 c) 2.61 d) 2.52 e) A face centered cubic cell of silver has a length of nm. Calculate the density of silver (g/cm 3 ). (Atomic weight: Ag = ). a) 10.5 b) 10.0 c) 11.0 d) 10.8 e) Above 476 C, plutonium crystallizes in a body centered cubic cubic with an edge length of nm. Below 451 C plutonium changes to a face centered cubic cell with an edge length of nm. Calculate the density (g/cm 3 ) above 476 C and below 451 C. The atomic weight of plutonium is 244. Page No.: 3

4 a) 16.8 and 16.2 b) 16.2 and 15.2 c) 16.8 and 15.9 d) 16.2 and 15.9 e) 15.2 and An element crystallizes in a body centered cubic lattice and the edge of the unit cell is nm. The density is g/cm 3. What is the atomic weight? a) 186 b) 190 c) 192 d) 181 e) An element crystallizes in a face centered cubic lattice and the edge of the unit cell is nm. The density is 1.83 g/cm 3. What is the atomic weight? a) 44.9 b) 47.9 c) 50.9 d) 39.9 e) An element crystallizes in a body centered cubic lattice and the edge of the unit cell is nm. The density is 7.20 g/cm 3. What is the atomic weight? a) 54.9 b) 55.8 c) 45.0 d) 51.8 e) CsI crystallizes in a cubic-type crystal system. The ionic radii for Cs + and I are and nm respectively. One can conclude that the Cs + ions occupy : a) an octahedral hole in a cubic close packed structure b) every other tetrahedral hole in a close packed structure c) every tetrahedral hole in a close packed structure d) a cubic hole in a simple cubic structure 26. CsI exists in a simple cubic arrangement. How many Cs + and I ions are contained in the unit cell? a) 4,4 b) 2,4 c) 2,2 d) 1,1 e) 4,2 27. CaS exists in a cubic close packed arrangement of S 2 ions in which Ca 2+ ions occupy 1/2 of the available tetrahedral holes. How many Ca 2+ and S 2 ions are contained in the unit cell? a) 2,2 b) 2,4 c) 1,1 d) 4,4 e) 4,2 Page No.: 4

5 28. Consider the following ionic substances and arrange them in order of increasing lattice energy. LiF CsI NaCl a) NaCl > LiF > CsI b) LiF > NaCl > CsI c) CsI > NaCl > LiF d) LiF > CsI > NaCl 29. Consider the following ionic substances and arrange them in order of increasing lattice energy. MgCl 2 CaCl 2 MgF 2 a) CaCl 2 > MgF 2 > MgCl 2 b) MgF 2 > MgCl 2 > CaCl 2 c) MgCl 2 > CaCl 2 > MgF 2 d) MgF 2 > CaCl 2 > MgCl Consider the following ionic substances and arrange them in order of increasing lattice energy. NaI KI LiCl a) NaI > KI > LiCl b) LiCl > NaI > KI c) KI > NaI > LiCl d) LiCl > KI > NaI 31. Which of the following has the highest critical temperature? a) F b) c) OH 32. Select the member of each of the following pairs that has the highest critical temperature? 1) OH or 2) or 3) or F. a) F b) OH c) OH F d) OH e) 33. Select the member of each of the following pairs that has the lowest critical temperature? 1) Ne or Ar 2) HBr or HCl 3) H 2 O or NH 3. a) Ar, HCl, H 2 O b) Ne, HBr, H 2 O c) Ne, HBr, H 2 O d) Ne, HCl, NH 3 e) Ar, HBr, H 2 O 34. Which of the following has the highest normal boiling point? a) NH 3 b) H 2 O c) HF 35. Which of the following has the lowest normal boiling point? a) - NH - b) - N( ) - c) Which of the following has the lowest normal boiling point? Page No.: 5

6 a) BiH 3 b) NH 3 c) PH 3 d) AsH 3 e) SbH Give the number of sites per molecule when hydrogen atoms may ne donated in hydrogen bond formation and the number of sites where electron pairs may be supplied for hydrogen bond formation : HO - OH. a) 2,6 b) 2,2 c) 4,2 d) 1,1 e) 2,4 38. Give the number of sites per molecule when hydrogen atoms may ne donated in hydrogen bond formation and the number of sites where electron pairs may be supplied for hydrogen bond formation : HO - a) 3,2 b) 2,4 c) 2,2 d) 2,3 e) 3,3 39. Which of the following can form intermolecular hydrogen bonds in the pure liquid? 1) HO - OH 2) HO - O - 3) - O - O - a) 3 only b) 2 only c) 1 only d) 2 and 3 e) 1 and Which of the following has the lowest heat of vaporization? a) SiH 4 b) SnH 4 c) CH 4 d) GeH Which of the following has the highest heat of vaporization? a) HO - O - b) - O - O - c) HO - OH 42. Which of the following has the lowest heat of vaporization? 1) - OH 2) - O - 3) - a) 3 b) 1 c) 2 Page No.: 6

7 A N S W E R S 1. c 16. b 31. c 2. c 17. b 32. d 3. c 18. b 33. d 4. c 19. a 34. b 5. c 20. a 35. b 6. c 21. a 36. c 7. b 22. d 37. e 8. b 23. d 38. e 9. b 24. d 39. e 10. b 25. d 40. c 11. b 26. d 41. c 12. b 27. d 42. c 13. a 28. b 14. a 29. b 15. a 30. b Page No.: 7