A 0.4021-g sample of a purified organic acid was dissolved in water and titrated potentiometrically. A plot of the data revealed a single end point after 19.31 mL of 0.1243 M had been introduced. Calculate the molecular mass of the acid.

The molar mass of the acid is 167.5 g/mol

Explanation:

A 0.4021-g sample of a purified organic acid was dissolved in water and titrated potentiometrically. A plot of the data revealed a single end point after 19.31 mL of 0.1243 M NaOH had been introduced. Calculate the molecular mass of the acid.

Step 1: Data given

Mass of the sample of a purified organic acid = 0.4021 grams

Molarity = 0.1243 M

Volume needed to reach the end point = 19.1 mL = 0.01931 L

Step 2: Calculate the number of moles NaOH

Moles NaOH = molarity NaOH  * volume

Moles NaOH = 0.1243 M * 0.01931 L

Moles NaOH = 0.00240 moles

Step 3: Calculate moles of the acid

We'll need 0.00240 moles of acid to neutralize 0.00240 moles of NaOH ( it's a single end point)

Moles acid = 0.00240 moles

Step 4: Calculate molar mass of the acid

Molar mass = mass / moles

Molar mass = 0.4021 grams / 0.00240 moles

Molar mass = 167.5 g/mol

The molar mass of the acid is 167.5 g/mol

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6

it's filtration, but this is an assumption so my apologies if i got this