## Molarity, weight %, Molality and other variables of solution

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Dhamnekar Winod
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### Molarity, weight %, Molality and other variables of solution

A solution is prepared by 10 g of solid para-dichlorobenzene (C6H4Cl2) in enough carbon tetrachloride to make a total of 350 mL of solution. The density of the resulting solution is 1.60 g/mL .

(a) Compute the molarity of the solution.

(b) Compute the weight % para-dichlorobenzene of the solution.

(c)Compute the molality of the solution.

(d) Compute the mole fraction of the solute.

(e) At 23℃ the vapor pressure of CCl4 is 100 mm. Compute the vapor pressure of the solution at this temperature.

(f) When a different solution of C6H4Cl2 is prepared, it is found to have a boiling point of 78.6℃. Given that $$K_b$$ = 5.0 ℃-kg/mol and the boiling point of pure CCl4 is 76.6℃, compute how many grams of solute are present in 100 grams of CCl4.

I am working on this question and all of its sub-questions.
Any science consists of the following process. 1) See 2)Hear 3)Smell,if needed 4)Taste, if needed 5)Think 6)Understand 7)Inference 8)Take decision [Believe or disbelieve, useful or useless, true or false, cause or effect, any other criteria]
ChenBeier
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### Re: Molarity, weight %, Molality and other variables of solution

a) 0,194 M
b) 1,79% w.w
c) 0,12 mmol/kg
d) 0,019
Dhamnekar Winod
Sr. Staff Member
Posts: 156
Joined: Sat Nov 21, 2020 10:14 am
Location: Mumbai[Bombay],Maharashtra State,India

### Re: Molarity, weight %, Molality and other variables of solution

My Computation work for answers to question (e) and (f).

My answer to (e)$$P_{CCl_4}=0.981 \times 100 mm=98.1 mm, P_{CCl_4}=$$ Vapor pressure of solution

My answer to (f) $$\Delta T_{bp}=K_{bp}\times m; m= \frac{\Delta T_{bp}}{K_b}=\frac{78.6^\circ C-76.6^\circ C}{5.02^\circ C-kg/mol}=0.40$$molal

Moles of C6H4Cl2= 0.40 kg/mol × 0.100 kg = 0.040 mol C6H4Cl2

Grams of C6H4Cl2 = 0.040 mol C6H4Cl2 × 147 g/mol =5.88 g C6H4Cl2
Any science consists of the following process. 1) See 2)Hear 3)Smell,if needed 4)Taste, if needed 5)Think 6)Understand 7)Inference 8)Take decision [Believe or disbelieve, useful or useless, true or false, cause or effect, any other criteria]
ChenBeier
Distinguished Member
Posts: 776
Joined: Wed Sep 27, 2017 7:25 am
Location: Berlin, Germany

Ok