Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

Volume of a Drop Delivered from a Buret The smallest practical volume that a beg

ID: 532840 • Letter: V

Question

Volume of a Drop Delivered from a Buret The smallest practical volume that a beginning user can deliver from a buret is 1 drop. Solutions from burets are generally delivered until a signal is observed in the target vessel. We try to control the delivered volume to be within 1 drop of the first detection of the signal. This part of the exercise is intended to provide the user of the buret with a sense of the volume, and therefore, the precision represented by that drop. The following data are collected in determining the average volume of a drop delivered from a 50 mL buret: What is the average volume of a drop in mL? Enter Your Answer: 0.05 To the nearest integer how many drops are in 1.00 mL of water? [It is useful to remember this number to estimate potential errors in future exercises.] Enter Your Answer 20

Explanation / Answer

Ans. #1. Your calculation is correct.

Volume of water released from burette = Final reading- Initial reading

                                                = 4.54 mL – 2.14 mL

                                                = 2.31 mL

Number of drops in 2.31 mL water = 49

Volume of 1 drop water = 2.31 mL/ No. of drops in 2.31 mL water

                                                = 2.31 mL/ 49 drops

                                                = 0.047 mL/ drop

                                                = 0.05 mL/ drop

#2. We have, volume of 1 drop = 0.05 mL

No. of drops in 1.00 mL water = 1.0 mL/ volume of 1 drop

                                                = 1.0 mL/ (0.05 mL/ drop)

                                                = 20 drops

Note As shown in picture, #2 is correct.

If volume of 1 drop were 0.07 mL, the no. of drops in 1.0 mL water would have been 14 drops (1.0 mL/ 0.07 = 14 drops)- that could have indicated 20 your #2 incorrect.