please help me thank you 121L QUESTIONS Indicate how each of the following would

Question

please help me thank you

121L QUESTIONS Indicate how each of the following would affect the value of the absorbance (too low, too high, no effect) of the indicated solution. Explain your answers. 1. A student prepares solution A using a 100.00 mL volumetric flask that is initially wet. a. A student rinses the 10.00 mL pipet only with DI water in the preparation of D (but does the rest of the procedure as instructed). b. A student fills the volumetric flask containing solution B so that the bottom of the meniscus is above the mark on the flask (but does the rest of the procedure as instructed). c.

Explanation / Answer

Beer's Law states that the absorbance of a sample is directly proportional to the concentration of solution. A= abc

So, for each of following error, we should observe the effect of error on concentration of solution.

a. No effect.

Explanation: A student prepares solution A in 100 ml volumetric flask that is initially wet. If volumetric flask is initially wet with water, there is no effect on concentration of solution A. The value of absorbance is unchanged.

b. Too low

Explanation: A student rinses the 10.00 mL pipet only with DI water in the preparation of D. He does not rinse the 10.00 mL pipet with solution D. Because the pipet has not been rinse with solution D, he might pick up less solution D, so concentration of solution D will be lower and give a lower absorbance.

c. Too high

Explanation: A student fills the volumetric flask containing solution B so that the bottom of the meniscus is below the mark on the flask; it means he measured less volume of solution B. So, the concentration of solution B will be higher. The value of absorbance is higher.

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