1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
lesya692 [45]
3 years ago
10

A solution is prepared by mixing 2.17 g of an unknown non-electrolyte with 225.0 g of chloroform. The freezing point of the resu

lting solution is –64.2oC. The freezing point of pure chloroform is – 63.5oC and its kf = 4.68oC m-1. What is the molecular mass of the unknown?
Chemistry
1 answer:
Deffense [45]3 years ago
6 0

Answer:

The molar mass of the unknown non-electrolyte is 64.3 g/mol

Explanation:

Step 1: Data given

Mass of an unknown non-electrolyte = 2.17 grams

Mass of chloroform = 225.0 grams

The freezing point of the resulting solution is –64.2 °C

The freezing point of pure chloroform is – 63.5°C

kf = 4.68°C/m

Step 2: Calculate molality

ΔT = i*kf*m

⇒ ΔT = The freezing point depression = T (pure solvent) − T(solution) = -63.5°C + 64.2 °C = 0.7 °C

⇒i = the van't Hoff factor = non-electrolyte = 1

⇒ kf = the freezing point depression constant = 4.68 °C/m

⇒ m = molality = moles unknown non-electrolyte / mass chloroform

0.7 °C = 1 * 4.68 °C/m * m

m = 0.150 molal

Step 3: Calculate moles unknown non-electrolyte

molality = moles unknown non-electrolyte / mass chloroform

Moles unknown non-electrolyte = 0.150 molal * 0.225 kg

Moles unknown non-electrolyte = 0.03375 moles

Step 4: Calculate molecular mass unknown non-electrolyte

Molar mass = mass / moles

Molar mass = 2.17 grams / 0.03375 moles

Molar mass = 64.3 g/mol

The molar mass of the unknown non-electrolyte is 64.3 g/mol

You might be interested in
What is the molecular structure of water? What are the physical and chemical properties of water?
Slav-nsk [51]
Water (H
2O) is a polar inorganic compound that is at room temperature a tasteless and odorless liquid, which is nearly colorless apart from an inherent hint of blue. It is by far the most studied chemical compound and is described as the "universal solvent" [18][19] and the "solvent of life".[20] It is the most abundant substance on Earth[21] and the only common substance to exist as a solid, liquid, and gas on Earth's surface.[22] It is also the third most abundant molecule in the universe.[21]

Water (H
2O)





NamesIUPAC name

water, oxidane

Other names

Hydrogen hydroxide (HH or HOH), hydrogen oxide, dihydrogen monoxide (DHMO) (systematic name[1]), hydrogen monoxide, dihydrogen oxide, hydric acid, hydrohydroxic acid, hydroxic acid, hydrol,[2] μ-oxido dihydrogen

Identifiers

CAS Number

7732-18-5 

3D model (JSmol)

Interactive image

Beilstein Reference

3587155ChEBI

CHEBI:15377 

ChEMBL

ChEMBL1098659 

ChemSpider

937 

Gmelin Reference

117

PubChem CID

962

RTECS numberZC0110000UNII

059QF0KO0R 

InChI

InChI=1S/H2O/h1H2 

Key: XLYOFNOQVPJJNP-UHFFFAOYSA-N 

SMILES

O

Properties

Chemical formula

H
2OMolar mass18.01528(33) g/molAppearanceWhite crystalline solid, almost colorless liquid with a hint of blue, colorless gas[3]OdorNoneDensityLiquid:[4]
0.9998396 g/mL at 0 °C
0.9970474 g/mL at 25 °C
0.961893 g/mL at 95 °C
Solid:[5]
0.9167 g/ml at 0 °CMelting point0.00 °C (32.00 °F; 273.15 K) [a]Boiling point99.98 °C (211.96 °F; 373.13 K) [6][a]SolubilityPoorly soluble in haloalkanes, aliphaticand aromatic hydrocarbons, ethers.[7]Improved solubility in carboxylates, alcohols, ketones, amines. Miscible with methanol, ethanol, propanol, isopropanol, acetone, glycerol, 1,4-dioxane, tetrahydrofuran, sulfolane, acetaldehyde, dimethylformamide, dimethoxyethane, dimethyl sulfoxide, acetonitrile. Partially miscible with Diethyl ether, Methyl Ethyl Ketone, Dichloromethane, Ethyl Acetate, Bromine.Vapor pressure3.1690 kilopascals or 0.031276 atm[8]Acidity (pKa)13.995[9][10][b]Basicity (pKb)13.995Conjugate acidHydroniumConjugate baseHydroxideThermal conductivity0.6065 W/(m·K)[13]

Refractive index (nD)

1.3330 (20 °C)[14]Viscosity0.890 cP[15]Structure

Crystal structure

Hexagonal

Point group

C2v

Molecular shape

Bent

Dipole moment

1.8546 D[16]Thermochemistry

Heat capacity (C)

75.375 ± 0.05 J/(mol·K)[17]

Std molar
entropy (So298)

69.95 ± 0.03 J/(mol·K)[17]

Std enthalpy of
formation (ΔfHo298)

−285.83 ± 0.04 kJ/mol[7][17]

Gibbs free energy (ΔfG˚)

−237.24 kJ/mol[7]
6 0
3 years ago
Compare and contrast the ease at which molecules are able to move relative to each other in the three states of matter
ANTONII [103]
The arrangement of molecules within the 3 phases of matter are shown in the picture. 

For the solid, the molecules are packed closely together. They don't have much space to move, so they just practically vibrate. For the liquid, the molecules are relatively farther from each other. The liquid molecules can flow freely but not as much as the gases. In the gases, the molecules are very far from each other. They are very sensitive to slight changes of pressure, volume and temperature.

5 0
3 years ago
A base
hichkok12 [17]
B, turns red litmus paper to blue
5 0
3 years ago
In a 63.17 g sample of SO3, how many grams are sulfur?
Evgesh-ka [11]

Answer:

25.30 gram

Explanation:

No of moles = given mass / molar mass

No of moles = 63.17/80.06

0.7890 moles

Mass of sulphar = no of moles× molar mass of sulphar

Mass of sulphur = 0.7890×32.065

25.30 gram

4 0
3 years ago
When diluting an acid with water always remember to:.
Alex777 [14]
Measure how much water has gone in, so you know the concentration.
3 0
2 years ago
Other questions:
  • Can a bad thermostat cause radiator to blow
    7·1 answer
  • Define mechanical energy. Using the example of the pendulum, explain how kinetic and potential energy relate to the mechanical e
    13·1 answer
  • You begin pouring sodium chloride into a glass of water. For a long time, the sodium chloride just dissolves in the water, but s
    11·1 answer
  • Which is one way to determine whether a reaction was a chemical reaction or a nuclear reaction?
    5·2 answers
  • If a rock had a mass of 20g explain how you would fund the density
    15·2 answers
  • Calculate the energy of the lasers in a Blu-ray player, which emit at a wavelength of 4.05x10−7 m.
    13·1 answer
  • Formula for calculating pressure​
    6·1 answer
  • Can you tell me name of Chemicals in food?​
    14·1 answer
  • True or false? In giant covalent structures the atoms form strong bonds by sharing electrons.
    14·1 answer
  • After 1 min, three radioactive nuclei remain from an original sample of six. Is it valid to conclude that t₁/₂ equals 1 min? Is
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!