Question

mp Delweer dusurance and transmittance? 4) You read the % transmittance on a spectrophotometer to be 25.8%, which means 25.8% of the initial light created has made it through your sample to the light detector. What is the absorbance value for 25.8% Transmittance? 5) What is the molar mass of FDC40 (Red Dye #40)? 6) If you had a 0.125 g/L solution of FDC40, what would the molarity of the solution be? 7) If you took 0.50 mL of the solution at the molarity calculated in problem 6 and added 9.50 ml of water to make a total volume of 10.00 mL. What would happen to the concentration of the FDC40 solution? Calculate the new concentration of the FDC40 solution.

please helps with 4-7

Answer 1

(4)

we know Transmittance and absorbance are inversely related, transmittance is the ratio of transmitted intensity to incident light intensity.

Absorbance A = 2 - log ( % T ) .-----(1)

if % transmittance is known.

absorbance A = 2 - log ( 25.8 )

since logrithm of 25.8 = 1.4116 , puting in equation (1) we get

Absorbance A = 2 - 1.4116 = 0​​​​.5883 Answer.