Experiment 23/24

PROPERTIES OF LIQUIDS and SOLIDS

Learning Objectives

Upon completion of this experiment, students will have experienced:

1. 1. (CLO1). Explain basic chemical concepts related to chemical changes, energy, and properties of matter.
  2. (CLO2). Apply the methods of scientific inquiry
  3. (CLO3). Analyze evidence to decide if generalizations or conclusions based on the obtained data are warranted
  4. (CHM 111 MLO5) Identify the intermolecular forces: dipole-dipole, hydrogen bonding, and dispersion forces present in a given substance.
  5. (MLO1) Explain how intermolecular forces and polarizability affect chemical and physical properties of liquids and solids: vapor pressure, boiling point, surface tension, capillary action, density, volatility and viscosity
  6. (MLO1) Calculate the vapor pressure of a liquid at a given temperature.
  7. (MLO1) Explain the number and location of atom or molecules in the unit cell (lattice point, side, edge or face) for simple cubic, body centered cubic, face centered cubic/cubic close packed and hexagonal close packed unit cells
  8. (MLO1) Calculate the atomic radius of an atom given its density and unit cell packing.
  9. (MLO1) Identify key characteristics and examples of the major types of crystals: ionic, covalent, molecular, or metallic.

Experiment 23/24 combined discusses the properties of liquids and solids.

The assignments that must be completed are:

Complete the pre writing assignment for the laboratory notebook
Complete the pre laboratory problems before coming to the class meeting.
Using the links, videos and resources provided to complete all parts of the laboratory report
Complete the conclusion paragraph for this assignment.

Virtual Experiment 23-24

Discussion

The background and discussion portion of this lab is available in the laboratory assignment

Experiment 23/24 Discussion

Pre laboratory Writing Assignment

Complete the pre laboratory writing assignment in your laboratory notebook. The prewriting must be completed before the laboratory session begins. Use the procedure document below to explain what has to be done to collect the necessary data of the lab. The writing should include a purpose/hypothesis of the experiment, a discussion or theory, a detailed step by step summary of the procedure explaining what data will be collected and how you will collect it. Data Tables or space to collect the data should be included within the procedure discussion. Look up any SDS on chemicals that you are not familiar.

Pre laboratory assignments

Complete the pre laboratory writing assignment in your laboratory notebook. The prewriting must be completed before the laboratory session begins. The writing should include a purpose/hypothesis of the experiment, a discussion or theory, a detailed step by step summary of the procedure explaining what data will be collected and how you will collect it. Data Tables or space to collect the data should be included within the procedure discussion. Look up any SDS on chemicals that you are not familiar.

Complete the pre laboratory problems before coming to the class meeting.

Virtual Experiment 23/24 pre lab problems

Procedure

Part I - Miscibility and Solubility

Determine the solubility or miscibility of the liquid and solid combinations of water, ethanol, hexane, NaCl and iodine. Describe your observations in the report. Answer the questions required in the assignment.

Part II - Extraction

Determine the solubility or miscibility of the solute in water or hexane. Describe your observations in the report. Answer the questions required in the assignment.

Experiment 23/24 Procedure

Part III - Capillary Action

Part A: Simulation

In this part of the experiment you will investigate the relationship between intermolecular forces and capillary action. Use the following simulation to determine the height of various liquids in a capillary tube. https://demonstrations.wolfram.com/CapillaryAction/ The required surface tension and specific gravity needed to measure the height of the liquid in the capillary tube is given in the procedure of the laboratory assignment.

Part B: Real liquids

Use several liquids and determine the surface tension in a glass capillary tube.

Part IV - Vapor Pressure and Evaporation rate of a liquid and Boiling

Part A: Simulation

Use this simulation to collect and graph the vapor pressure of several substances every 10 degrees between 0 and 100 degrees.

Create the graph of the vapor pressure and temperature.

Part B. Evaporation

Determine the rate of evaporation of several liquids.

http://billvining.com/mmlib_sims/#gen_11_7

Part C: Boiling Points.

Use the following videos to understand when a liquid boils under both temperature and pressure conditions. Watch the Water in a vacuum chamber - Triple point to observe when all three states of water can coexist.

https://youtu.be/zzVtbvVS2lQ

mrsciguy

A classroom demonstration of the effects of lowering the air pressure on the boiling point of water.

https://youtu.be/y4BGV7-1lhs

Cody'sLab

I put water in a vacuum chamber to bring it to its triple point.

Part V. Crystal structure and Unit cells

We will build models using the Solid State Model Kit. The manual for the kit contains directions for building 100 different solid state structures. We will be building specific structures for this lab. I have build most of these models in the video below and have taken pictures of several of the models.

After watching the video, describe the structure in the pictures below or on the video and answer the appropriate questions for each model.

The following websites contain cell structure that also can be used to answer these questions

3D crystal models: http://www.ibiblio.org/e-notes/Cryst/Cryst.htm
Interactive 3D Chemistry: https://www.chemtube3d.com/

Cubic close packed (ccp) and the hexagonal close packed (hcp) structures.
http://www.ibiblio.org/e-notes/Cryst/FCCcp.html versus http://www.ibiblio.org/e-notes/Cryst/hex.html

Simple cubic structure or Primitive Cubic
https://www.chemtube3d.com/simple-cubic-lattice/
http://www.ibiblio.org/e-notes/Cryst/Cubic4.html

Body centered cubic structure
https://www.chemtube3d.com/_bccfinal/
http://www.ibiblio.org/e-notes/Cryst/BCC2.html

Cubic Close packing/Face centered cubic
https://www.chemtube3d.com/ccp-cubic-close-packing/
http://www.ibiblio.org/e-notes/Cryst/FCC.html

Hexagonal close packing - https://www.chemtube3d.com/hexagonal-close-packing/

NaCl - https://www.chemtube3d.com/_rocksaltfinal/
http://www.ibiblio.org/e-notes/Cryst/NaCl2.html

Video of models being built

Exp 23/24 Crystal Structure models

GMT20200603-014151_Summer-202_1920x1080.mp4

Coordination number 8
8 coord. hole
Page 93

Coordination number 6
Octahedral hole
Page 93

Coordination number 4
Tetrahedral hole

Primitive or Simple Cubic unit cell
Page 9

SCC Eight unit cells
note the yellow ball is on the corner of all 8 cells

Simple Cubic Unit cell
Body Diagonal
Page 10

note this is the same structure as the 8 coordinate structure.

Body Centered cubic unit cell
Page 18

Cubic Close Packed
note the third layer is not directly over the first layer

Cubic Close Packed
body diagonal

Face Centered Cubic Unit cell
Page 26

Comparison of the face centered cubic (FCC) with the diagonal of the cubic close packed (CCP) structures. Note that the face is visible on the ccp structure if we rotate and look at a slightly different angle. They are the same structures.

Hexagonal Close Packed
first layer

Second Layer

Hexagonal close packed (hcp)
third layer - note that the atoms in the first and third layer are directly over each other.

Compared to the Cubic close packed (ccp) - note the first and third layers are not directly over each other.

Sodium Chloride unit cell
Page 33

NaCl unit cell extended

Zinc sulfide blend
Page 51

Tetrahedral holes filled

https://youtu.be/S-rE7CJBrQo

Unit Cell Chemistry, Atomic Radius, Density & Edge Length Calculations, Close Packed Structures

Engineer Thileban Explains - This video tutorial explains how to solve unit cell chemistry problems associated with closed packed structures such as the body centered cubic structure and the face centered cubic structure also known as the cubic closest packing structure. This video explains how to calculate the atomic radius, edge length and density of a cubic crystal lattice structure. You need to know the coordination number or number of atoms per unit cell associated with a given cubic crystal structure. This video contains plenty of examples and practice problems.

Part VI. Density and atomic radius.

We will determine the atomic radius of a metallic element from a cube of the pure metal after determining the density of the metal.

Use the pictures of the measurements for several metals in the procedure part V of the laboratory assignment to complete the calculations for the atomic radius of both a bcc and ccp unknown. compare the atomic radius to the accepted radius of the element and answer the questions in the assignment.

Once you have determined the density of the unknown. determine it's identity using the density of elements from least to greatest: https://www.angstromsciences.com/density-elements-chart
Density of the elements can also be looked up on https://www.webelements.com/

The elements pack as different unit cells. We will be using metal elements that pack as cubic close pack (ccp) or body centered cubic (bcc) as possible unknowns. See the table for possible unknowns.

Atomic radii of the elements can be found on webelements under atomic properties of the element or on the website: https://environmentalchemistry.com/yogi/periodic/atomicradius.html Generally the atomic radius is given in pm (picometers) but this last link gives the radius in an older unit of angstrom (1 A = 100 pm)

Report and Conclusion Paragraph

Complete the data and result tables, graphs, calculations and answer all required questions.

Complete a conclusion paragraph using the RERUNS method. A discussion of how to write a conclusion paragraph is given in Appendix D: How to Write a Formal Laboratory Report

Experiment 23/24 report

O-Experiment 23/24

The Virtual Experiment 23/24 is on the website

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