I am doing a cyclic Voltammetry lab in one of my chemistry classes this week and

Question

I am doing a cyclic Voltammetry lab in one of my chemistry classes this week and I'm completely stumped as to how to make the solutions:

Prepare 25 mL of a 2 mM solution of quinone with 0.1 M TBAHFP as the supporting electrolyte in acetonitrile using a 25 mL volumetric flask.

It also says that I will need to add successive amounts of dry ethanol to the solution to make 0.05 M, 0.1 M, 0.2 M, 0.5 M and 1 M in ethanol. The molecular weight of ethanol is 46.0634 g mol^-1 and the density is 0.789 g mL^-1.

Any help would be greatly appreciated. Please show all work so I can understand this stuff. Thanks!

Explanation / Answer

C1V1 = C2V2

25 * 2 x 10^-3 M = 0.1 * V2

V2 = 0.5 mL

So, 0.5 mL of TBAHFP in acetonitrile is required . You have to get more than 0.1 g of TBAHFP for this experiment

Volume = 25 mL

Molarity = given mass * 1000 / Molar mass * Volume( in mL)

0.05 = m * 1000 / ( 46.0634 * 25)

m = 0.058 g

Therefore 0.058 g of dry ethanol is required to make a 25 mL solution of 0.05 M

For 0.1 M it will be 0.116 g of dry ethanol

For 0.2 M t will be 0.232 g of dry ethanol

For 0.5 M it will be 0.580 g of dry ethanol

For 1 M it will be 1.16 g of dry ethanol

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