A 7.27-gram sample of a compound is dissolved in 250. grams of benzene. The freezing point of this solution is 1.02°C below that of pure benzene. What is the molar mass of this compound? (Note: Kf for benzene = 5.12°C/m.) Ignore significant figures for this problem. Group of answer choices 36.5 g/mol 146 g/mol 292 g/mol 5.79 g/mol 73.0 g/mol

Answers

Answer 1

Answer:

The correct answer is 146 g/mol

Explanation:

Freezing point depression is a colligative property related to the number of particles of solute dissolved in a solvent. It is given by:

ΔTf = Kf x m

Where ΔTf is the freezing point depression (in ºC), Kf is a constant for the solvent and m is the molality of solution. From the problem, we know the following data:

ΔTf = 1.02ºC

Kf = 5.12ºC/m

From this, we can calculate the molality:

m = ΔTf/Kf = 1.02ºC/(5.12ºC/m)= 0.199 m

The molality of a solution is defined as the moles of solute per kg of solvent. Thus, we can multiply the molality by the mass of solvent in kg (250 g= 0.25 kg) to obtain the moles of solute:

0.199 mol/kg benzene x 0.25 kg = 0.0498 moles solute

There are 0.0498 moles of solute dissolved in the solution. To calculate the molar mass of the solute, we divide the mass (7.27 g) into the moles:

molar mass = mass/mol = 7.27 g/(0.0498 mol) = 145.9 g/mol ≅ 146 g/mol

Therefore, the molar mass of the compound is 146 g/mol


Related Questions

When does carbon dioxide absorb the most heat energy?
during freezing
during deposition
during sublimation
during condensation

Answers

During sublimation

This has been posted on here before so you could’ve searched it lol.

Best of luck :))

Answer:

during sublimation

Explanation:

just took the test

You are given 3 liquid samples – A, B, C and told that one is water, one is ethanol, and one is ether (d=0.700 g/mL). Each sample is 10.0 mL. the masses are as follows: A = 10.0 g, B= 7.00 g, C = 8.00 g. Identify each of the substances using density problems.

Answers

Answer:

im just trying to get work done i will help u if i knew it

Identify the oxidizing and reducing agent in the following reaction, and determine which element is oxidized and which is reduced. Fe2+(aq) + ClO2(aq) → Fe3+(aq) + ClO2–(aq) ClO2 is the reducing agent and Fe2+ is the oxidizing agent . Fe is oxidized and Cl is reduced. g

Answers

Answer:

Explanation:

Fe⁺²(aq) + ClO₂(aq) → Fe⁺³(aq) + ClO₂⁻(aq)

Here oxidation number of Fe is increased from +2 to +3 , so Fe is oxidised .

The oxidation number of Cl is reduced from + 4 to +3  so Cl is reduced .

So ClO₂(aq) is oxidising agent and Fe⁺²(aq) is reducing agent .

I need help with this​

Answers

Answer:

2 nitrogen molecules are present

1 oxygen molecule is present

1 n2o molecules are present

give reason deliquescent substance truns into liquid when exposed to atmosphere air​

Answers

answer: it absorbs the moisture content

What is the frequency of a wave having 4.90 x 10 -12 J of energy?

Answers

Answer:

The answer is

[tex] \huge 7.40 \times {10}^{21} Hz[/tex]

Explanation:

To find the frequency of the wave we use the formula

[tex]f = \frac{E}{h} \\ [/tex]

where

E is the energy

f is the frequency

h is the Planck's constant which is

6.626 × 10-³⁴ Js

From the question

E = 4.90 × 10-¹² J

So we have

[tex]f = \frac{4.90 \times {10}^{ - 12} }{6.626 \times {10}^{ - 34} } \\ [/tex]

We have the final answer as

[tex]7.40 \times {10}^{21} \: \: Hz[/tex]

Hope this helps you

During photosynthesis, plants and some other organisms use energy from the sun to convert (change): carbon dioxide (CO2) and water (H2O) into ____________ (O2) and __________ (C6H12O6)

Answers

Answer:

CO2 + H2O → O2 + C6H12O6

CO2 = carbon dioxide

H2O = water

O2 = oxygen

C6H12O6 = glukose

How is matter divided?

Answers

matter can be divided into 2 ways:

if it’s a pure substance it can be broken down into elements and compounds

and if it’s a mixture it could be physically combined with other structures to separate their original components

Hopefully i could help!!

Which is denser a liquid or solid why?

Answers

Answer:

Liquids are usually less dense than solids but more dense than air. Temperature can change a liquid's density. For example, increasing the temperature of water causes the molecules to spread farther apart. The farther apart the molecules are, the less dense the water is.

Answer:

Solids are usually much more dense than liquids and gases, but not always.

Explanation:

Mercury, a metallic element that is a liquid at room temperature, is denser than many solids. Aerogel, a very unusual human-made solid, is about 500 times less dense than wate

.
Ag+1, NO3-1
+
Na+1, I-1
->

Answers

Answer:

0.3+Na

Explanation:

Time is always the same on the same line of latitude or longitude

Answers

Answer:

Longtitude

No explanation :)

If you worked at a job for $9.00/hour, what type of correlation is the number of hours worked and your take-home pay?

Answers

Answer:

There are no options to this question, however, it can be answered. The answer is:

POSITIVE CORRELATION

Explanation:

Correlation refers to the relationship between two variables. It shows how related two variables are to one another. Hence, when two variables are correlated, there exists a relationship between them. Correlation can either be positive or negative depending on how related they are.

A positive correlation is that correlation in which the two variables are influenced to go in the same direction. That is, when one variable increases, the other variable increases as well and vice versa. This is the case in this question regarding the correlation between number of hours worked and take-home pay.

As the number of hours worked increases, the take-home pay also increases and vice versa. Hence, it is a type of POSITIVE CORRELATION

Which statement BEST explains why the Moon is visible from the Earth?


1) The Moon reflects light from the Sun.

2) The Moon is always lit up by the Sun for us to see.

3) The Moon reflects light from the Earth.

4) The Moon produces its own light through radiation.

Answers

Answer: The answer is the ''The moon is always lit up by the sun for us to see.''

Explanation: The moon is directly illuminated by the sun.

2 is the correct answer

Calculate the number of moles in 2.60 grams of SnO2 ? Please show your work to receive credit.

Answers

Answer:

There are 0.017252 moles in SnO2

Explanation:

n= m/M

n=2.6/(118.710 + 2(16))

n= 2.6/150.71

n= 0.017252

Remeber to round based on the significant digits in the question.

19. A beam of light can be seen as it passes through a(n).
a. Element
I
b. Compound
C. Solution
d. Heterogeneous Mixture
A beam of light can be seen as it passes through a

Answers

Element???????? I don’t really know I’m sorry
It’s not a solution I don’t think because a solution is a mixture of particles so small they cannot be seen. Im like 90% sure it’s not solution I’m so sorry if I’m wrong.

a 108ml sampl of gas has a mass of 77.96mg at a pressure of 1140mmhg and temperature of 183°c .what is the molar mass of the gas ?​

Answers

Answer:

146.85 g/mol

Explanation:

PV=nRT

n=mass/molar mass

covert from mmhg to atm = 0.184 atm

convert from ml to L= 0.108 L

convert from degree C to K= 456.15 K

convert from mg to g= 0.07796g

then rearrange the formula:

n=PV/RT

=(0.184)(0.108)/(0.08206)(456.15)

n= 5.308*10^(-4)

rearrange the n formula interms of molar mass:

Molar mass= mass/n

=0.07796/(5.308*10^-4)

molar mass= 146.85g/mol

Answer:

Molar mass = 20 g/mol

Explanation:

Given data:

Volume of gas = 108 mL

Mass of gas = 77.96 mg (77.96/1000 = 0.08 g)

Pressure of gas = 1140 mmHg

Temperature of gas = 183°C

Molar mass of gas = ?

Solution:

First of all we will calculate the number of moles of gas.

PV = nRT

R = general gas constant = 0.0821 atm.L/ mol.K

Now we will convert the units and then we will put the values in formula.

Volume of gas = 108 mL× 1 L/1000 mL= 0.108 L

Pressure of gas = 1140 mmHg× 1 atm / 760 mmHg = 1.5 atm

Temperature of gas = 183+273 = 456 K

PV = nRT

1.5 atm ×0.108 L = n × 0.0821 atm.L/ mol.K ×456 K

0.162 atm.L =  n ×37.44 atm.L/ mol

n = 0.162 atm.L/37.44 atm.L/ mol

n = 0.004 mol

Molar mass of gas:

Number of moles = mass/molar mass

0.004 mol = 0.08 g / molar mass

Molar mass = 0.08 g /0.004 mol

Molar mass = 20 g/mol

What is the particle behavior of an liquid?

Answers

Answer: The particles are moving fast but close together.

Answer:

its in the explanation.

Explanation:

1.In liquids, particles are quite close together and move with random motion throughout the container. Particles move rapidly in all directions but collide with each other more frequently than in gases due to shorter distances between particles.

2.It assumes the shape of the part of the container which it occupies particles can move/slide past one another.

Hope this helps. :)

how many moles are in a 4.2 gram gold sample

Answers

The answer is 196.96655 hope this helps

What kind of metal is Cu?


Transition metal


Alkaline earth metal


Alkali metal



Answers

Answer: Transition metal

Explanation: Copper is definitely a transition metal because the Cu2+ ion has an incomplete d level.

How might ocean waves affect a beach over thousands of years? Explain your answer.

Answers

Answer:

Explanation:

Well a oceans waves could erode the beach it it is a rocky one, it can wash the sand out and can cause rocks to fall.

Search Results
Featured snippet from the web
The erosion of rock formations in the water, coral reefs and headlands create rock particles that the waves move onshore, offshore and along the shore, creating the beach. Continual erosion of the shoreline by waves also changes the beach over time. One change that erosion can cause is the appearance of a headland

Thermal Energy moves from a colder region to a warmer region. *
True
False

Answers

False.

There is more thermal energy (faster moving particles) in a warmer region, so they spread out over time, warming up the other regions and losing energy.

Please mark as Brainliest.

The answer above is correct my dude

Ok

A plant part that contains a tiny new plant, or embryo
seed
spore
root
flower

Answers

I think it’s seed or a spore

Which atom has exactly 15 protons?

Answers

Answer:

Phosphorus

Explanation:

An ion formed from an atom has a 1- charge. The number of electrons present in the ion is 36 and the number of neutrons is 46. Identify the element by typing the name. For example: Hydrogen or Sodium.

Answers

Answer:

Bromine can become an ion when it gains an electron. Br- is a negative ion. Its known as an anion. Bromine has 35 protons=35 electrons. one added electron gives it 36 electrons  and it becomes an anion.

Explanation:

Bromine can have isotopes having 44 and 46 neutrons.

What was one main point of Dalton’s atomic theory?
A. That atoms were made up of positive and negative charges
B. That atoms changed as they formed compounds
C. That atoms has a nucleus at the center
D. That atoms made up the smallest form of matter

Answers

The main point of Dalton’s atomic theory is that the atoms are made up the smallest form of matter. Hence Option (D) is Correct

What is Dalton's Atomic Theory ?

The 5 main points of Dalton's Atomic theory was ;

Elements are composed of extremely small particles called atoms that are indivisible and indestructible

All atoms of a given element are identical; they have the same size, mass, and chemical properties

Atoms of 1 element are different from the atoms of all other elements

Compounds are composed of atoms of more than 1 element. The relative number of atoms of each element in a given compound is always the same.

Chemical reactions only involve the rearrangement of atoms. Atoms are not created or destroyed during chemical reactions.

Therefore, The main point of Dalton’s atomic theory is that the atoms are made up the smallest form of matter. Hence Option (D) is Correct

Learn more about Atom here ;

https://brainly.com/question/657632

#SPJ2

Answer:

D is correct

Explanation:

8. Why is the magnetic force considered to be a noncontact force?

Answers

Answer:

Magnetic forces are non contact forces; they pull or push on objects without touching them. Magnets are only attracted to a few 'magnetic' metals and not all matter. Magnets are attracted to and repel other magnets.

Hope this helps!!!

Explanation:

Phosphoric acid, which is commonly used as rust inhibitor, food additive and etching agent for dental and orthopedic use, can be synthesized using a two-step thermal process. In the first step, phosphorus and oxygen react to form diphosphorus pentoxide:

P4(l)+ 5O2(g) → P2O5()

In the second step, diphosphorus pentoxide and water react to form phosphoric acid:

P2O5(g)+ 3H2O → 2H3PO4

Write the net chemical equation for the production of phosphoric acid from phosphorus, oxygen and water. Be sure your equation is balanced.

Answers

Answer:

P4(l) + 5O2(g) + 6H2O(l) → 4H3PO4(aq)

Explanation:

Step 1

P4(l)+ 5O2(g) → 2P2O5()

Step 2

2P2O5(g)+ 6H2O(l) → 4H3PO4(aq)

Overall balanced equation;

P4(l) + 5O2(g) + 6H2O(l) → 4H3PO4(aq)

Notice carefully that the correct coefficients were used to balance the equations and obtain the accurate overall reaction equation. All the steps involved were shown above. Reactants that occur on both sides cancel out and do not appear in the final equation.

Violet light has a wavelength of 4.50 x 10-12 m. What is the frequency?*

3 points

1.5 x10^20 1/s

0.0135 1/s

6.77x10^19 1/5

3x10^8 1/s

Green light has a frequency of 6.73 x 1014 1/s. What is the wavelength?*

3 points

2.24x10^6 m

4.46x10^-7 m

2.02 x 10^23 m.

4.95 x 10^-24 m

3 points

What is the energy (Joules) of violet light with a frequency = 3.43 x 10^14

1/s? *

4.54x10^-19 J

1.99x10^-25 J

1.93 x 10^-48 J

2.27 x 10^-19 J

Answers

Answer:

Frequency = 6.67x10¹⁹ s⁻¹

Wavelength = 4.46x10⁻⁷m

e = 2.27x10⁻¹⁹J

Explanation:

To convert frequency to wavelength and vice versa we use the equation:

Wavelength = Speed of light / Frequency

Speed ligth is 3x10⁸m/s

For a wavelength of 4.50x10⁻¹²m:

4.50x10⁻¹²m = 3x10⁸m/s / Frequency

Frequency = 3x10⁸m/s / 4.5x10⁻¹²m

Frequency = 6.67x10¹⁹ s⁻¹

For a frequency of 6.73x10¹⁴s⁻¹:

Wavelength = 3x10⁸m/s / 6.73x10¹⁴s⁻¹

Wavelength = 4.46x10⁻⁷m

And energy, e, from frequency, is obtained as follows:

e = h ₓ frequency

Where h is Planck's constant, 6.626x10⁻³⁴J*s

e = 6.626x10⁻³⁴J*s*3.43x10¹⁴s⁻¹

e = 2.27x10⁻¹⁹J

Vocabulary Terms: Please copy down the definitions for words below from the Smart Screen.

Length is defined as
Height is defined as
Circumference is defined as
Perimeter is defined as
Diagonal is defined as
Diameter is defined as

Answers

Answer:

Explanation:

Length: Length is a measure of distance

Height:The measurement from base to top or (of a standing person) from head to foot.

Circumference:The enclosing boundary of a curved geometric figure, especially a circle

Perimeter: Length of the outline of a shape.

Diagonal:A line segment that goes from one corner to another, but is not an edge. So when we directly join any two corners (called "vertices") which are not already joined by an edge, we get a diagonal. Diagonals of Polygons.

Diameter: A straight line passing from side to side of any figure or body, through its center.

How is stress and strain related to elastic deformation?

Answers

Answer:

elastic materials like rubber have small k

Explanation:

is the change in length divided by the original length of the object.

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