When 271. mg of a certain molecular compound X are dissolved in 25.0g of benzene C6H6, the freezing point of the solution is measured to be 0.5°C. Calculate the molar mass of X. If you need any additional information on benzene, use only what you find in the ALEKS Data resource. Also, be sure your answer has a unit symbol, and is rounded to 2 significant digits.
molal freezing point depression constant (Kf)
°C·kg·mol−1 of benzene is 5.07

11g/mol is the molar mass of X

Explanation:

The freezing point depression occurs in a solvent by the addition of a solute. The equation is:

ΔT = Kf*m*i

Where ΔT is change in freezing point (5.5°C - 0.5°C = 5.0°C)

Freezing point of benzene is 5.5°C

Kf is molal freezing point depression of benzene (5.07°C*kg/mol)

m is molality of the solution in moles/kg of solvent

And i is Van't Hoff factor (1 for all solutes dissolved in benzene)

Replacing to solve molality:

5.0°C = 5.07°C*kg/mol*m*1

0.986mol / kg = molality

As the mass of the solvent is 25.0g = 0.025kg:

0.025kg * (0.986mol/kg) = 0.0247 moles

As molar mass of X is the ratio between mass in grams and moles, the molar mass of X is:

0.271g / 0.0247moles =

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.