Using the standardized NaOH solution, the student weighs out 0.2550g of a solid unknown acid and finds that 28.50mL of the NaOH solution is required to reach an end point with the acid. Calculate the molar mass of the unknown acid, assuming the acid is diprotic.
I worked this for you earlier. I'll look for it if you can't find it.
where's it at?
where's it at? i couldn't find it
I did work it; however, I didn't post it. Here is is.
I did work it; however, I didn't post it. Here is is.
http://www.jiskha.com/display.cgi?id=1398473570
thank you!
To calculate the molar mass of the unknown acid, we need to determine the number of moles of acid used in the reaction with NaOH.
Step 1: Calculate the number of moles of NaOH used
To find the number of moles of NaOH used, we use the equation:
moles of NaOH = volume of NaOH (in L) × concentration of NaOH (in mol/L)
However, we need to calculate the concentration of NaOH first.
Step 2: Calculate the concentration of NaOH
The concentration of NaOH can be determined by titration. In this case, the volume of NaOH used (28.50 mL) and the mass of the unknown acid (0.2550 g) are given. Additionally, it is stated that NaOH is standardized, meaning its concentration is known.
Step 3: Use the balanced chemical equation to determine the mole ratio
Since the acid is diprotic, the balanced equation will involve two moles of NaOH for every mole of the acid.
Step 4: Calculate the number of moles of the unknown acid
Using the mole ratio from the balanced chemical equation, we can determine the number of moles of the unknown acid.
moles of acid = moles of NaOH × (1 mole of acid / 2 moles of NaOH)
Step 5: Calculate the molar mass of the unknown acid
Finally, divide the mass of the unknown acid by the number of moles calculated in Step 4 to determine the molar mass.
molar mass of acid = mass of acid (in grams) / moles of acid