Harr: Clinical Chemistry Questions and Answers Rated A+

Harr: Clinical Chemistry Questions and Answers Rated A+ Which formula correctly describes the relationship between absorbance and %T ? A. A = 2 - log %T B. A = log 1/T C. A = -log T D. All of these options D. All of these options D Absorbance is proportional to the inverse log of transmittance. A = -log T = log 1/T Multiplying the numerator and denominator by 100 gives: A = log (100/100 X T) 100 X T = %T, substituting %T for 100 X T gives: A = log 100/%T A = log 100 - log %T A = 2.0 - log %T For example, if %T = 10.0, then: A = 2.0 - log 10.0 log 10.0 = 1.0 A = 2.0-1.0 = 1.0 A solution that has a transmittance of 1.0 %T would have an absorbance of: A. 1.0 B. 2.0 C. 1% D. 99% B. 2.0 B A = 2.0 - log %T A = 2.0 - log 1.0 The log of 1.0 = 0 A = 2.0 In absorption spectrophotometry: A. Absorbance is directly proportional to transmittance B. Percent transmittance is directly proportional to concentration C. Percent transmittance is directly proportional to the light path length D. Absorbance is directly proportional to concentration D. Absorbance is directly proportional to concentration D Beer's law states that A = a × b × c, where a is the absorptivity coefficient (a constant), b is the path length, and c is concentration. Absorbance is directly proportional to both b and c. Doubling the path length results in incident light contacting twice the number of molecules in solution. This causes absorbance to double, the same effect as doubling the concentration of molecules. Which wavelength would be absorbed strongly by a red-colored solution? A. 450 nm B. 585 nm C. 600 nm D. 650 nm A. 450 nm A A solution transmits light corresponding in wavelength to its color, and usually absorbs light of wavelengths complementary to its color. A red solution transmits light of 600-650 nm and strongly absorbs 400-500 nm light. A green-colored solution would show highest transmittance at: A. 475 nm B. 525 nm C. 585 nm D. 620