Chemistry, 18.02.2020 00:53 bxbykyah

At 39.5 o C, the vapor pressure of pure acetone (MM = 58.08 g/mol) is 400.0 torr. If 15.0 grams of an unknown molecule is dissolved in 485.0 g acetone, the vapor pressure decreases to 361.8 torr. What is the molar mass of the solute?

Answers: 1

Show answers

Answers

Answer from: xxtonixwilsonxx

The molar mass of unknown molecule is 157.07 g/mol

Explanation:

The equation used to calculate relative lowering of vapor pressure follows:

$\frac{p^o-p_s}{p^o}=i\times \chi_{solute}$

where,

$\frac{p^o-p_s}{p^o}$ = relative lowering in vapor pressure

i = Van't Hoff factor = 1 (for non electrolytes)

$\chi_{solute}$ = mole fraction of solute = ?

p^o = vapor pressure of pure acetone = 400 torr

p_s = vapor pressure of solution = 361.8 torr

Putting values in above equation, we get:

$\frac{400-361.8}{400}=1\times\chi_{A}\\\\\chi_{A}=0.0955$

This means that 0.0955 moles of unknown molecule is present in the solution

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Moles of unknown molecule = 0.0955 moles

Mass of unknown molecule = 15.0 grams

Putting values in above equation, we get:

$0.0955mol=\frac{15.0g}{\text{Molar mass of unknown molecule}}\\\\\text{Molar mass of unknown molecule}=\frac{15.0g}{0.0955mol}=157.07g/mol$

Hence, the molar mass of unknown molecule is 157.07 g/mol

Answer from: Quest

explanation:

the largest database of organic compounds lists about 10 million substances, which include compounds originating from living organisms and those synthesized by chemists. the number of potential organic compounds has been estimated at 1060—an astronomically high number. the existence of so many organic molecules is a consequence of the ability of carbon atoms to form up to four strong bonds to other carbon atoms, resulting in chains and rings of many different sizes, shapes, and complexities. the simplest organic compounds contain only the elements carbon and hydrogen, and are called hydrocarbons. even though they are composed of only two types of atoms, there is a wide variety of hydrocarbons because they may consist of varying lengths of chains, branched chains, and rings of carbon atoms, or combinations of these structures. in addition, hydrocarbons may differ in the types of carbon-carbon bonds present in their molecules. many hydrocarbons are found in plants, animals, and their fossils; other hydrocarbons have been prepared in the laboratory. we use hydrocarbons every day, mainly as fuels, such as natural gas, acetylene, propane, butane, and the principal components of gasoline, diesel fuel, and heating oil. the familiar plastics polyethylene, polypropylene, and polystyrene are also hydrocarbons. we can distinguish several types of hydrocarbons by differences in the bonding between carbon atoms. this leads to differences in geometries and in the hybridization of the carbon orbitals.

Answer from: Quest

just did the assignment and the answer was #1 +2 n

Another question on Chemistry

Chemistry, 22.06.2019 12:30

Which statement is true about this reaction? 14n+1h 15o it is a practical source of energy on earth. it occurs only outside the solar system. its product is heavier than each of its reactants. it shows the critical mass of an element.

Answers: 2

Answer

Chemistry, 23.06.2019 10:10

In a covalent bond, two atoms are held together by the attraction between . the number of covalent bonds that an atom can form depends on the number of in the atom.

Answers: 2

Answer

Chemistry, 23.06.2019 17:10

Which substance produces hydroxide ions in solution? a. an arrhenius acid b. an arrhenius base c. a brønsted-lowry acid d. a brønsted-lowry base e. an amphoteric substance

Answers: 3

Answer

Chemistry, 23.06.2019 18:50

Why are very high temperatures and pressures required for fusion to occur? to generate the neutrons that are needed to break the nuclei o to overcome the repulsion between the protons in the nuclei that join to maintain the proper conditions to keep the chain reaction going to keep the uranium fuel separate from the control rods

Answers: 1

Answer

You know the right answer?

At 39.5 o C, the vapor pressure of pure acetone (MM = 58.08 g/mol) is 400.0 torr. If 15.0 grams of a...

Questions