Question

Calculate the χacetone and χcyclohexane in the vapor above the solution. p°acetone = 229.5 torr and p°cyclohexane = 97.6 torr.

Answer 1

First calculate the mole fraction of each substance:
Acetone: 2.88 mol ÷ (2.88 mol + 1.45 mol) = 0.665
Cyclohexane: 1.45 ÷ (2.88 mol + 1.45 mol) = 0.335
Raoult's Law: P(total) = P(acetone) · χ(acetone)  + P(cyclohexane) · χ(cyclohexane).
P(total) = 229.5 torr · 0.665 + 97.6 torr · 0.335
P(total) = 185.3 torr
χ for acetone: 229.5 torr · 0.665 ÷ 185.3 torr = 0.823 
χ for cyclohexane:  97.6 torr · 0.335 ÷ 185.3 torr = 0.177

Answer 2

The completed structure of ${\text{C}}{{\text{H}}_{\text{3}}}{\text{SSC}}{{\text{H}}_{\text{3}}}$ is shown in the attached image.

Further explanation:

Lewis structure:

In covalent molecules, different atoms are bonded to each other and this bonding between these atoms is shown with help of diagrams known as Lewis structures, Lone pairs are also indicated by such structures. These are also known as Lewis dot diagrams, Lewis dot structures or electron dot diagrams.

Lewis structure of ${\mathbf{C}}{{\mathbf{H}}_{\mathbf{3}}}{\mathbf{SSC}}{{\mathbf{H}}_{\mathbf{3}}}$ (Refer to the structure in the attached image):

The total number of valence electrons of ${\text{C}}{{\text{H}}_{\text{3}}}{\text{SSC}}{{\text{H}}_{\text{3}}}$ is calculated as follows:

Total valence electrons = [(2) (Valence electrons of C) + (2) (Valence electrons of S) + (6) (Valence electrons of H)]

$\begin{aligned} {\text{Total valence electrons}}\left( {{\text{TVE}}} \right) &= \left[ {\left( {\text{2}} \right)\left( {\text{4}} \right) + \left( {\text{2}} \right)\left( {\text{6}} \right) + \left( 6 \right)\left( 1 \right)} \right] \\ & = 26 \\ \end{aligned}$  

In ${\text{C}}{{\text{H}}_{\text{3}}}{\text{SSC}}{{\text{H}}_{\text{3}}}$, the total number of valence electrons is 26. In this molecule, each carbon forms three single bonds with three discrete hydrogen atoms and one single bond with sulfur atoms. So 16 electrons are used up in formation of six C-H bonds and two C-S bonds. Each sulfur atom forms one bond with other sulfur atom so 2 electrons are used up in formation of one S-S bond. Out of 26 total electrons, 18 electrons are utilized in formation of bonds in ${\text{C}}{{\text{H}}_{\text{3}}}{\text{SSC}}{{\text{H}}_{\text{3}}}$ and eight electrons are left unutilized and act as four lone pairs. Since carbon forms four bonds and each hydrogen atom forms one bond, four lone pairs are present on both sulfur atoms.

Learn more:

1. Molecular shape around each of the central atoms in the amino acid glycine: brainly.com/question/4341225
2. Draw resonating structures of azide ion: brainly.com/question/6002848

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Molecular structure and chemical bonding

Keywords: Lewis structure, valence electrons, CH3SSCH3, 26, 18, lone pairs, carbon, sulfur, hydrogen, four lone pairs, 2, 16.