Could someone help me with this please?
In chemistry, we did a lab in which he put brands of commerical vinegar in a microplate. We put in 10 drops of each vinegar in each plate thinger then we added 1 drop of phenolphthalein and then put in as many drops of NaOH as it took to turn the solution pink.
I need help with this lab question:
1)From the two closest trials, find the average number of drops of NaOH required to titrate each vinegar. Use this average number of drops and the given molarity of the NaOH to calculate the molarity of acetic acid in each of the brands of vinegar. Assuming identical volumes for the drops of vinegar and the drops of NaOH solution, the ratio of reacting volumes in liters is the same as the ratio of reacting volumes in drops.
The average number of drops is 64.5 for one of the brands. I think the equation I should use goes like this:
C1=(C2*V2)/V1
where c=concentration and v=volume and the 1 and 2 are subscripts. 2 is NaOH and I think 1 is the vinegar.
Am I on the right track? Please help!
yes.
molarity vinegar x volume vinegar = molarity NaOH x volume NaOH.
You may have used some unit other than molarity for concentration .
thanks
Yes, you are on the right track! The equation you mentioned, C1 = (C2 * V2) / V1, is indeed the correct equation to use in this case.
In the equation, C1 represents the concentration of acetic acid in the vinegar (the solute), V1 represents the volume of acetic acid in the vinegar, C2 represents the concentration of sodium hydroxide (NaOH) solution (the titrant), and V2 represents the volume of NaOH solution.
To calculate the molarity of acetic acid in the vinegar, you need to rearrange the equation slightly to solve for C1.
C1 = (C2 * V2) / V1
In this equation, you have all the necessary values except for C1, which is what you want to calculate. The given molarity of NaOH is the concentration of the NaOH solution (C2), and the volume of NaOH solution required to titrate the vinegar is the average number of drops (V2). The volume of vinegar is not explicitly given, but since the drops of vinegar and drops of NaOH solution have identical volumes, you can use the average number of drops (V1) as the volume of vinegar as well.
So, you can substitute the values into the equation and solve for C1:
C1 = (C2 * V2) / V1
C1 = (given molarity of NaOH * average number of drops of NaOH) / average number of drops of vinegar
Let's say the given molarity of NaOH is 0.1 M and the average number of drops of NaOH is 64.5. Plug in these values along with the average number of drops of vinegar and calculate C1.
C1 = (0.1 * 64.5) / average number of drops of vinegar
Note: Ensure that the units are consistent throughout the calculation. If the volume is given in mL, make sure the molarity is also expressed in M (mol/L) and not in mol/mL.
By solving this equation, you will find the molarity of acetic acid in the vinegar. Repeat the calculation for each of the different brands of vinegar to determine the molarity of acetic acid in each brand.