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Here you will find material for Experiment 2 - Properties of Matter. This includes detailed guides for the pre-lab, data sheet, post-lab, and quiz questions. Experiment 2 will illustrate extensive and intensive properties categories. Specific properties that fall under one of these categories and you should focus on are appearance, odor, boiling point, mass, volume, density, and solubility. Remember, the lab may change or be modified from semester to semester!
Experiment 2 is broken up into two main parts - A. Physical Properties and B. Chemical Properties
A. PHYSICAL PROPERTIES
Physical properties will explore appearance & odor, density, boiling point and solubility. Using the data obtained from these procedures, you will then identify an unknown substance.
B. chemical PROPERTIES
The second part explores chemical properties. This will be performed through combustion with air and reaction with sodium. Observations of the reactions will be recorded.
what you need
Below or a list of items you will need for lab. These items can be bought at the campus bookstore and from UH American Chemical Society (ACS). However, you may find these cheaper on sites like Amazon (links below).
CALCULATOR (LINK)
A scientific calculator is needed for calculations on quizzes. Some labs have calculations that need to be turned in before leaving.
LAB GOGGLES (LINK)
Required eye protection. Must be worn at the start of the experiment and until leaving
COMBINATION LOCK (LINK)
A combination lock is required to lock your equipment drawer for the semester.
LAB COAT (LINK)
A lab coat is required and must be worn once lab begins.
LAB MANUAL (LINK)
Specifically, General Chemistry Laboratories A Freshman Workbook. The lab manual will have all the experiment procedures you will be performing during the semester including their respective datasheet and postlab questions
what to expect
The information provided below are things you will need to know and understand to complete this experiment successfully. We have also included parts of the lab that may give you difficulties, potential bottlenecks and workarounds so you can finish the experiment efficiently. Remember, the information given by TA should have the highest importance and supersedes all information provided on this page.
bottlenecks
This experiment has many potential bottlenecks since many physical properties procedures must be repeated to get an average and then also repeated for every unknown. The chemical properties section may also present a bottleneck since there are limited hoods and the TA may perform the sodium reaction instead of letting groups completing it themselves. Some suggestion to mitigate these are given below.
Group and Split Tasks
Have one person do the quick, short procedures while others do the more time intensive ones. The following are quick and short:
Physical Properties - Appearance & Odor
Physical Properties - Solubility
Chemical Properties - Combustion with Air
For the more time intense procedures, you can have one person focus on one unknown while the other person does the other unknown.
Things to Focus on
intensive & extensive properties
Intensive properties are ones that DO NOT depend on the quantity or amount of the substance. Specific examples of intensive properties for this lab are appearance, odor, boiling point, density and solubility.
Extensive properties are ones that depend on the quantity or amount of the substance. Specific examples of extensive properties for this lab are mass and volume.
These properties can be further broken down into physical or chemical properties. Physical properties DOES NOT change the substance whereas chemical properties do change the substance.
With these properties or combination of properties, we can identify unknown substances by measuring and observing the properties of the unknown substances. In this lab, you will observing and recording different properties. Using this data and comparing references values, you will identify two unknowns.
safety
Pay attention to these following. They may show up on your quiz.
Unknowns may be flammable
Sodium reacts violently with water
Calculations
Density & Significant figures
Density = Mass ÷ Volume
Density is a physical property that involves mass and volume. It is calculated by taking the mass of a substance divided by its volume. Having 2 of the 3 values will enable you to calculate the third value. Keep in mind that we are assuming the mass from the balance is accurate. In this experiment, you will be measuring the mass of a specific amount of volume transferred of the unknown. From this, the density can be calculated and compared to references.