Reserpine is a substance that is used as a tranquilizer and sedative. A solution containing 0.20g of reserpine in 5.0 g of camphor (K_f = 40.0 ⁰C/m) gives a freezing point 2.63⁰C below the freezing point of pure camphor. Determine the molecular weight of reserpine.

(A) 486.5g/mol

(B) 497.4g/mol

(C) 552.6g/mol

(D) 608.4g/mol

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Question 4

The melting point of pure benzene is 278.70 K and K_f 4.90 K/m. When 2.10 g of an unknown solute is added to 50.0g of benzene, the freezing point of the solution is 277.60 K. Determine the molecular weight of the unknown.

(A) 97.12g/mol

(B) 150.05g/mol

(C) 187.09g/mol

(D) 208.83g/mol

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Question 5

The freezing point of a solution prepared with 3.54g of acetamide (C₂H₅ON) to 200.0g of naphthalene (C₁₀H₈) was 78.2⁰C. Pure naphthalene solidified at 80.2⁰C. Determine the freezing point constant for naphthalene.

(A) 5.7K/m

(B) 6.7K/m

(C) 7.7K/m

(D) 8.7K/m

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Question 6

How many grams of antifreeze (C₂H₆O₂) need be added to 200.0g of water to have a solution that will not freeze at the temperature -10 ⁰C? K_f of water is 1.86⁰C/m

(A) 13.3

(B) 33.3

(C) 66.7

(D) 100.0

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