A student weighed out a sample of acid powder and found the mass to be 1.42 g. When the solution turned pink, the student read t

Question

4 years ago

11

A student weighed out a sample of acid powder and found the mass to be 1.42 g. When the solution turned pink, the student read t

he burette accurately and found it to be 32.48 mL. If the base concentration is 0.1426 M, what is the molecular weight of the unknown acid

Chemistry

1 answer:

aalyn [17] · Answer 1 · 2021-12-30T22:43:02+03:00

Answer:

306.6g/mol

Explanation:

To calculate molecular weight you need to know how many grams ou have in a determined amount of moles of substance. As you have the mass of the sample (1.42g), you need to find how many moles are, as follows:

The reaction of the acid HX with the base YOH is:

HX + YOH → H₂O + YX

<em>1 mole of acid reacts per mole of base.</em>

<em />

In a titration, the solution turned pink when moles base = moles acid.

Moles of base that the student added (Using the volume and molarity of the solution) are:

32.48mL = 0.03248L ₓ (0.1426 moles base / L) = 0.004632 moles of base

As the titration is in equivalence point, there are 0.004632 moles of the acid

Molecular weight (Ratio between grams of sample and its moles) is:

1.42g / 0.004632 moles =