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Vinegar, which is just a dilute acetic acid solution, is very common and versati

ID: 887255 • Letter: V

Question

Vinegar, which is just a dilute acetic acid solution, is very common and versatile. The concentration of store-bought vinegar around a 5.0 % solution by mass, and its density is approximately 1.01 g/mL.

(a) Suppose I dilute this vinegar into a bottle to 3 parts water + 1 part vinegar (in other words, I make a solution that is 25% as strong as it was) . Determine the molarity of this new vinegar solution.

(b) If I use 2 cups (473.2 mL) of this new vinegar solution from part (a) to help create a cleaning solution for my windows, how many molecules of acetic acid is this?

(c) How many atoms of carbon are in 2 cups of this new vinegar you made in part (a)?

Explanation / Answer

Assume that we have 100g solution, we have 5g of acetic acid.
#mole of acetic acid (C2H4O2) = 5/60 = 1/12 mol
Volume of solution = m/d = 100/1.01 = 99ml
Concentration of acetic acid = n/v = (1/12) / (99x10^-3) =0.84175M

a. V1M1 = V2M2 so, M2 = (V1M1)/V2
with V1 is the volume of old vinegar
   V2 is the volume of new vinergar
   M1 is the concentration of old vinegar
   M2 is the new concentration of new vinegar
and V2 = 4 V1
so, M2 = (1/4)M1 = 0.25 x 0.84175M = 0.2104M

b. #mole of new vinegar = MxV= 0.2104M x 0.4732L =0.099956mol
0.099956mol vinegar x(6.022x10^23 molecules vinegar/ 1 mol vinegar) = 6.00x10^22 molecules vinegar