Updated Nov.16/04 ----------------------------------------------------------------------------------------- NUMERICAL ANSWERS TO ASSIGNED TUTORIAL PROBLEM SETS FOR CHEM205 FROM KOTZ & TREICHEL'S CHEMISTRY & CHEMICAL REACTIVITY ----------------------------------------------------------------------------------------- NOTE: none of the answers from Ch.7 have been verified NOTE: "^" means "raised to the power of..." to indicate scientific notation... NOTE: I cannot represent superscripts/subscripts here -- so...for polyatomic ions, I have left a space between the ion's formula and its charge Ch. Q# Answer Units SFs Comments ----------------------------------------------------------------------------------------- 7 14 n = principle Q.N. --> Energy & size n = 1,2,3,... l = angular momentum Q.N. --> shape of subshells l = 0,1,2,3,...,n-1 m(l) = magnetic Q.N. --> orientation...specifies exactly which orbital in subshell e- occupies m(l) = -l to +l in integer increments i.e., 0, +/-1, +/-2, +/-3,...+/-l 7 21a red, orange, yellow 21b blue 21c blue 7 23a 261 m 3 corresponds to 0.863 wavelengths 23b 3.06 m 3 corresponds to 73.6 wavelengths 7 25 4.8x10^-19 J/photon 2 wavelength 4.1x10^-7m; frequency 7.3x10^14 s-1 7 29a radar (least E per photon) 29b microwaves 29c red light 29d ultraviolet radiation 29e gamma-rays (most E per photon) 7 31 3.7x10^-19 J/photon 2 insufficient E (all radiation of >540 nm wavelength) 7 33a infrared region 33b none are shown in Fig.7.9 (none are in visible region) 33c highest E line has shortest wavelength, 837.761 nm 33d 2.29531x10^-19 J/photon 6 7 37a n=3 to n=2 37d n=3 to n=5 7 43 5.6x10^-12 m 2 7 45 1.41x10^-33 m 3 from speed = 313 m/s 7 47a a 4d orbital 47b n=5, l=0 --> a single s orbital n=5, l=1 --> set of 3 p orbitals n=5, l=2 --> set of 5 d orbitals n=5, l=3 --> set of 7 f orbitals n=5, l=4 --> set of 9 g orbitals total of 5^2=25 orbitals in n=5 shell 47c an f subshell has 7 orbitals: m(l) = 0, +/-1, +/-2, +/-3 7 53a incorrect; when n=3, max value of l = 2 53b incorrect; when l=3, can have m(l) = 0, +/-1, +/-2, +/-3 7 57 2f and 1p are incorrect; not allowed l values for given n value 7 67 319 kJ/mol 3 energy of a mole of 375nm photons 7 69 5.9x10^4 photons 2 for photons of 4.2x10^19 J each 7 73 1s, 2s, 2p, 3s, 3p, 3d, 4s 7 77 Modern view of atom: based on e- simultaneously behaving as wave & particle. Atomic structure described using WAVE description of electron to define regions around nucleus where have highest probability of finding electrons of specified energies. 7 79 (a) and (b) 7 83 8.0x10^25 photons 2 note: this question on heat transfer isn't really fair for Chem205 from 130J absorbed by eye; & 1.7x10^-24 J/photon of 0.120 m radiation 7 87a size, E and shape 87b 0, 1, 2 87c f 87d 4; 2; -2 87e p: l=1, 1 nodal plane; d: l=2, 2 nodal planes 87f f 87g 2d, 3f 87h n=2, l=1, m(l)=2 is not valid (invalid m(l) value) 87i (i) 3; (ii) 9; (iii) none; (iv) 1 7 87