A solution of carbon tetrachloride and acetic acid (CH3COOH) that is 50% carbon tetrachloride by mass is boiling at 98.6 °C. The vapor is collected and cooled until it condenses to form a new solution. Calculate the percent by mass of carbon tetrachloride in the new solution.

The percent by mass of carbon tetrachloride in the new solution is 72.6

Explanation:

Molecular weight of Carbon Tetrachloride is 154 g/mol

Molecular weight of CH3COOH is 60g/mol

Mass fraction of CCl4 is 0.5

Mass fraction of CCl4 is (0.5/154)/{(0.5/154) + (0.5/60)}

Mass fraction of CCl4 is X = 0.2803 and Y = 1-X

As per Raoul’s law

Y Pt = X * P1

Pt = X * P1 + YP2

Pt = 0.2803 * 1377 + (1-0.2803) * 519

Pt = 759.557 torr

Substituting the given values we get  

Y1 = X1P1/Pt

Y1 = 0.2803 * 1377/759.557

Y1 = 0.508

Mass fraction  

(0.508)(154)/{( (0.508)(154)) + (1-0.508)(60)}

= 0.726 = 72.6 %

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.