Consider a solution of 0.400M Co(NO_3)_2, by your lab instructor. You are requir
ID: 523436 • Letter: C
Question
Consider a solution of 0.400M Co(NO_3)_2, by your lab instructor. You are required to make the following dilute concentrations: 0.160M and 0.240M solutions. You are provided the following glassware: 5.0 mL Mohr pipet and 18 mm times 150 mm test tubes. Describe how you would prepare each solution, and support your description with your calculations. (Recall M times V = M times V) where M is the molarity of the concentrated solution, V is the volume of the concentrated solution, M is the molarity of the dilute solution, and Vd is the volume of the diluted solution.) In your own words, explain, in detail, what you will be learning during this lab. Address the chemical principles and, laboratory skills, in your answer.Explanation / Answer
1. Source stock is 0.400 M. Required diluted concentrations are 0.160 M and 0.240 M.
We know that V1M1=V2M2 where V1 and M1 are respectively volume and molarity of initial stock and V2 , M2 are final volume and molarity respectively.
If the volume of final stock we made is 5 ml then
Similarly for the 0.240 M concentration we need 3 ml of 0.400 M solution which must be diluted to 5 ml
y*0.400=5*0.240 or y=3 ml
x*0.4=5*0.160 or x=2 ie 2 ml 0.400 M stock should be taken and it must be diluted to total 5 ml to get the required concentration ie 0.160 M