PROPERTIES OF LIQUIDS and SOLIDS

Learning Objectives

Upon completion of this experiment, students will have experienced:

1. 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. (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

      5. (MLO1)  Calculate the atomic radius of an atom given its density and unit cell packing.

      6. (MLO1)  Identify key characteristics and examples of the major types of crystals: ionic, covalent, molecular, or metallic.

Pre laboratory writing 

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 you are not familiar with.    

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

Part B.   Watch these three videos and report on the rate of evaporation for ethanol, acetone and water.  

Evaporation and Intermolecular Attractions:   https://youtu.be/Oq-hb0sMspw

Evaporation project:   https://youtu.be/xZHv1Ye0JIk

Evaporation of ethanol, acetone and water:  https://youtu.be/wS872X6_Zww 

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.  

Part V.   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)