Final answer:
The concentration of a solution has a direct relationship with absorbance, according to the Beer-Lambert law, and an inverse relationship with transmittance. As concentration increases, absorbance goes up while transmittance decreases.
Step-by-step explanation:
The concentration of a solution is directly related to its absorbance. According to the Beer-Lambert law, absorbance (A) is equal to the molar absorptivity (ε) multiplied by concentration (c) and the path length (l). The relationship can be expressed as A = ε * c * l. Typically, path length is set to 1 cm, which allows for a straightforward calculation of concentration when you know the compound's molar absorptivity and measure its absorbance at the maximum absorption wavelength (λmax).
With regards to transmittance, it is inversely related to absorbance. Transmittance refers to the percentage of light that passes through a sample. The more concentrated the solution, the lower the transmittance will be, as more light is absorbed by the solute particles within the solution. The relationship between transmittance and absorbance is logarithmic; specifically, absorbance is the negative logarithm of transmittance.
When the concentration increases, absorbance increases and transmittance decreases. This can be observed when looking at the calibration curve generated by plotting known concentrations against measured absorbance values. Such curves are used in various biological and chemical analyses to determine unknown sample concentrations based on their absorbance readings.