Question 18:
To determine the concentration of substance Z based on its absorbance (A600) at 600 nm, you can use Beer-Lambert Law, which relates absorbance to concentration. The equation can be written as:
\[ A600 = k \times C \]
where:
- \( A600 \) = Absorbance at 600 nm
- \( k \) = constant for substance Z (in units of ng/μL per absorbance unit)
- \( C \) = concentration of substance Z (in ng/μL)
To find the concentration \( C \), you can rearrange the equation:
\[ C = \frac{A600}{k} \]
Given that the constant \( k \) for substance Z is 80 ng/μL, the equation becomes:
\[ C = \frac{A600}{80} \]
Question 19:
Now, using the equation for concentration derived from Question 18:
Given \( A600 = 0.59 \),
The concentration \( C \) can be calculated as follows:
\[ C = \frac{0.59}{80} \]
\[ C = 0.007375 , \text{ng/μL} \]
To express the answer to one decimal place:
\[ C = 0.0 , \text{ng/μL} \] (since 0.007375 rounded to one decimal place is 0.0)
So, your answer for Question 19 is 0.0 ng/μL.