Since the unkown acid is monoprotic, this also equals the number of moles of acid to use. A typical molar mass for an unknown acid in this experiment is 380 g/mol. Using this molar mass, calculate the mass (in grams) of unknown acid you should use per titration.
1.Suppose that 10.2 mL of 0.0512 M NaOH were required to titrate a sample of unkown acid. How many moles of NaOH were used? The answer i got is 0.00052224
2. Assuming that the unknown acid sample in question 1 had a mass of 0.177g, what is the molar mass of the unknown acid?
I tried everything and cant figure out number 2.
I tried:
0.00052224=0.1777/x
0.00052224=380/x
To find the molar mass of the unknown acid (question 2), you need to use the information given in question 1 and apply the concept of stoichiometry.
Let's start with question 1: Suppose that 10.2 mL of 0.0512 M NaOH were required to titrate a sample of unknown acid. To find the number of moles of NaOH used, you can use the formula:
moles = concentration × volume
Given:
Concentration of NaOH (C₁) = 0.0512 M
Volume of NaOH (V₁) = 10.2 mL = 0.0102 L
Using the formula:
moles of NaOH = C₁ × V₁
= 0.0512 M × 0.0102 L
= 0.00052224 moles
Based on your calculations, the number of moles of NaOH used is 0.00052224 moles.
Now, for question 2: Assuming that the unknown acid sample in question 1 had a mass of 0.177 g, we can calculate the molar mass of the unknown acid by using the concept of stoichiometry.
Stoichiometry relates the moles of one substance to the moles of another substance based on the balanced chemical equation. In this case, we assume the balanced chemical equation between the unknown acid and NaOH is:
Unknown acid + NaOH → NaA (salt) + H₂O
Since the unknown acid is monoprotic (capable of donating only one proton or hydrogen ion per molecule), the mole ratio between the unknown acid and NaOH is 1:1. Therefore, the number of moles of the unknown acid is also 0.00052224 moles.
Given:
Mass of unknown acid (m) = 0.177 g
Number of moles of unknown acid (n) = 0.00052224 mol
To find the molar mass (M) of the unknown acid, you can use the formula:
Molar mass = Mass (m) / Moles (n)
Substituting the values:
Molar mass = 0.177 g / 0.00052224 mol
Calculating this expression gives the molar mass of the unknown acid.
You leave us in the dark with this. Instead of saying you tried everything, post what you tried and let us find the error. This we're playing guessing games.
0.177, not 0.1777. Then
0.000522 = 0.177/x
x = 0.177/0.000522 = 338.9 which rounds to 339.
Your line three doesn't follow from line 2. Line 2, except for the extra 7 in the grams is ok. I don't know where the 380 came from. If you had finished and shown how you obtained x I might be more definitive. Sometimes these data bases count the answer incorrect if you use too many significant figures. You are allowed only 3 places. You never actually solved for x so I can't tell where you made the error.