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quantitative chem lab quiz 5a

quantitative chem lab quiz 5a - [mi Quant1tat1ve Analy31s...

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Unformatted text preview: [mi Quant1tat1ve Analy31s Laboratory //L Ill] L ‘\ )\ / / L " ' Chem 22-85.(S 2008) —. Tu, Th section V; Quiz #5 (25 points total) <3 I Name: W km 1111:; ,, 171; 3 , él’ 6 pts. How much energy (in kilojoules) IS carried by 0 e mol of photons of red light with )t= 650 nm? . , g 1 , -34 3 i113? 3' f :1 What excitation does 3a molecule undergo after absorbing a photon? (h= 6. 626 X 10 J__s_, c —— 3. 00 x 10 ' ~- 1 ll) 2 m/ N= 6.022 10 l '34 - 9.111 S a x “1° ) 1; 42¢ 1/1 I: 2 41111103 /<.T; E- Nee _/#_._._.;._._ r , -* . ' {ch/'14 E : ééléx/OMW 11,;- 7/555 M0 Q A 1 1110 ~ 22/; 53654) .71} A - . \ur l v ’4 )K «(if )1” (I 'g'i (4 pts. ) The absorbance of a 2. 55 x 10'5 M solution of a compound 1510.815 at a /wéavelength of 266 nm in i a 2. 00 cm cell. Calculate the molar absorptivity at 266 nm. 1 1 5“ f" “L: ’ 5 ’9 25 4:55; 1’21“” rim £9 A ‘i/"Zrmhji—QMSSX/O') ; / X} g: r p / 60 y") 3. Two part question: ‘ a. (2 pts. ) How are the absorbance of a mixture and the absorbance of the individual components 9 ,, 1 .1 I .. making up that mixture related. Me fig“ rédwzc a; ,11, ., 12’ g 1- 27 7M. .5441. 1/ ‘ I ,1 41 “Ma/l J;L dngrvflr‘rfl' G¥4/1(/ fly' “'1 /C /2 b (2 pts.) Solution 1 has an absorbance 075 at a given wavelength and s lEgon 2 has an absorbance of 0.60 at the same wavelength If three parts of solutionl is xed with two parts 1 6’0 that will be the absorbance of the mixture at the same Wavelength; assuming no reaction occurs? €31 WA }/I,73’f+,&)3 ’ y "97"!” ’ (.2, , [KL/fl 2’ La con/(m/rw 1 "A i 2’2) + I .L, f T 4. A compound with a molar mass of/9216 was dissolved 1n a InglL volumetric flask. A .001 mL fl; 5 L c aliquot was withdrawn, placed 1n a 10 mL volumetric flask, and diluted to the mark. Thew absorbance at 340 nm was 0. 465 1n a 1.000 cm cuvet. The molar absorptivity for this compound at 340 nm is 2340 — 'yé 3’ 5890 M' cm'. , / A: A4. / / a (4 pts) Calculate the concentration in the cuvet. A : 1 75> / / S'WWW}..:' ””7“; / (1 y ’ LL 7. 8 57’ K 'Y . (2 pts.) What was the concentration of compound in the 10 mL flask? “ a 7 ,. 1;?" ‘m lmL[M13 2 IOML [7872/11 /£)')i‘ 2 f ’ /2 ’9mL[”11)"1”"‘1" Mr ; 5871/11)” (5 pts ) How many milligrams of the compound were used to make the 10 mL solution? RIOMLIMQ: 1 \ Mo/ ‘: /~. ) -,4.‘.'1r‘ L ...
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