Question

🔹BOILING POINT AND FREEZING POINT OF SOLUTION

1. a solution is made of 2.00g sucrose in 100.00 g H2O. (Molecular weight of sucrose is 342 g/mol). Calculate the (a) Boiling point and (b) freezing point of the solution 

🔸OSMOTIC PRESSURE 

1. What is the osmotic pressure of a solution made up of 2.00g sucrose (C12H22O11) in 100mL of solution at 30°C? 

Answer 1

1.Sucrose mass = 2g

Molar mass of sucrose=342g/mol

No. of moles of sucrose $=\dfrac{2}{342}=0.0005847$

Mass of water= 100g

Molar mass of water = 18g/mol

Number of moles of water $=\dfrac{100}{18}=5.55 mol$

So using rault's law-

  $\dfrac{31.8-P_s}{31.8}=\dfrac{1.14}{32.94}$

$31.8-P_s=1.1005 \\[9pt] p_s=30.6995 mm hg$

2.

Osmotic pressure-

$\Pi= csT$

$=\dfrac{2}{100}\times 1000\times 0.0821\times 303 \\[9pt] =498.34 mm hg$