Calculate the mass of a nonvoltile solute (molar mass 40gm/mol) which

1.	Calculate the mass of a nonvoltile solute (molar mass 40gm/mol) which should be disolve in 114gm octane reduce its vapour pressure to 80%
Answer» ANSWER : Let the vapour pressure of pure OCTANE be p10. Then, the vapour pressure of the octane after DISSOLVING the non-volatile solute is 80/100 p10 = 0.8 p10. Molar mass of solute, M2 = 40 g mol - 1 Mass of octane, w1 = 114 g Molar mass of octane, (C8H18), M1 = 8 × 12 + 18 × 1 = 114 g mol - 1 Applying the relation, => (p10 - p1) / p10 = (W2 x M1 ) / (M2 x w1 ) => (p10 - 0.8 p10) / p10 = (w2 x 114 ) / (40 x 114 ) => 0.2 p10 / p10 = w2 / 40 => 0.2 = w2 / 40 => w2 = 8 g Hence, the required mass of the solute is 8 g. Mark as brainliest ^_^

Calculate the mass of a nonvoltile solute (molar mass 40gm/mol) which should be disolve in 114gm octane reduce its vapour pressure to 80%

Answer»

Let the vapour pressure of pure OCTANE be p10.

Then, the vapour pressure of the octane after DISSOLVING the non-volatile solute is 80/100 p10 = 0.8 p10.

Molar mass of octane, (C8H18), M1 = 8 × 12 + 18 × 1 = 114 g mol - 1

Applying the relation,

=> (p10 - p1) / p10 = (W2 x M1 ) / (M2 x w1 )

=> (p10 - 0.8 p10) / p10 = (w2 x 114 ) / (40 x 114 )

=> 0.2 p10 / p10 = w2 / 40

=> 0.2 = w2 / 40

=> w2 = 8 g

Hence, the required mass of the solute is 8 g.