Question

mistry Course Home <Assignment 13 Chap 13: Determining Molar Mass Problem 13.80 - Enhanced - with Feedback Lauryl alcohol is a nonelectrolyte obtained from coconut oil and is used to make detergents. A solution of 6.00 of Lauryl alcohol in 0.100 kg of benzene freezes at 3.8 °C Part A You may want to reference (Pages 542-552) Section 13.5 while completing this problem What is the approximate molar mass of lauryl alcohol? Express your answer using two significant figures. AEO O ? MME 8/mol Submit Request Answer Provide Feedback

Answer 1

Part A:

Given data,

Mass of Benzene = 0.100 kg

Freezing point of solution = 3.8⁰C

Melting point of benzene = 5.5⁰C

K_f = 5.12⁰C/ m

$\Delta$T_f = 5.5 - 3.8

= 1.7⁰C

$\Delta$T_f = K_f x m where m is molarity

1.7 = 5.12 x m

m = 1.7 / 5.12

= 0.332 m

m = Mass / Molar mass x 0.100

0.332 = 6 / Molar mass x 0.100

molar mass = 6 / 0.332 x 0.100

= 6 / 0.0332

= 180.722 g / mol