Okay, so i know this is pretty basic stuff, but i totally forgothow to do it. Yo
ID: 675772 • Letter: O
Question
Okay, so i know this is pretty basic stuff, but i totally forgothow to do it. You dont have to do the whole thing at all, butjust a start because i forgot the equation on how to do it.Assume that you have 1, 2, 5, and 10 ml pipets and 25 ml volumetricflask. Describe in detail how you would prepare a solutionwith a concentration near 0.10 M From a 0.650 M stocksolution. calculate the final concentration of the dilutedsolution ( it won't be exactly 0.10 M). It should be within10% of the 0.10 M.
Thank you so much!
Explanation / Answer
I think there are multiple solutions to this, and many ways ofachieving a solution. I use the tried and tested method of... guessand check! You want to decrease the concentration of your 0.650 M stocksolution by a factor of about 6.5 (= 0.650 M / 0.1 M), in order toget a final concentration of 0.1 M. The actual concentration range(10% allowance) is 0.9*0.1 M = 0.09 M to 1.1*0.1 M = 0.11. You can achieve a dilution factor of 5.0 by: Take 5 mL of 0.650 M solution (0.006*0.650 =0.00325 moles) Dilute up to themark in the 25 mL volumetric flask: new concentration is 0.00325 /0.025 = 0.13 M This is still to concentrated. Try diluting this further - we needa factor of about 1.3 (= 0.13 M / 0.1 M), which is almost nodilution at all. So take the majority of the solution and dilute itjust a little bit: Take 20 mL of 0.13 M solution (0.020*0.13 =0.0026 moles) Dilute up to themark in the 25 mL volumetric flask: new concentration is 0.0026 /0.025 = 0.104 M This concentration is in the desired range of 0.9 - 1.1 M. Sorry I couldn't provide an equation - I always had troubleunderstanding dilution factors (always forget whether it's final /initial, or the other way around...), so I never bothered to learnit that well. XD
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