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Chemistry LibreTexts

Chem 9 Experiments

  • Page ID
    93981
    • 1: Measurements in the Laboratory (Experiment)
      All measuring devices are subject to error, making it impossible to obtain exact measurements. Students will record all the digits of the measurement using the markings that we know exactly and one further digit that we estimate and call uncertain. The uncertain digit is our best estimate using the smallest unit of measurement given and estimating between two of these values. These digits are collectively referred to as significant figures.
    • 2: Paper Chromatography of Gel Ink Pens (Experiment)
      Chromatography is a method of physically separating mixtures into its individual components and is used to identify unknown components in mixtures. There are several types of chromatography; all types employ a mobile phase or eluent (liquid or gas), which is forced through a stationary phase (a solid or semi-solid). Mixtures are separated because some components will be more attracted to the stationary phase while some components will be more attracted to the mobile phase.
    • 3: The Properties of Oxygen Gas (Experiment)
      Oxygen is one of the most abundant elements on this planet. Our atmosphere is 21% free elemental oxygen. Oxygen is also extensively combined in compounds in the earths crust, such as water (89%) and in mineral oxides. Even the human body is 65% oxygen by mass.   The objectives of this laboratory are: To generate (and collect) oxygen gas via the decomposition of hydrogen peroxide. To investigate the properties of oxygen, particularly as an agent of combustion.
    • 4: Detection and Absorption of Ultraviolet Light (Experiment)
      Solar energy (sunlight) contains light we can see, and some we cannot. Visible light has wavelengths of 750 to 400 nm. Ultraviolet (UV) light has shorter wavelengths, cannot be seen, and has higher energy. Infrared (IR) radiation is the major source of heat for Earth. Though UV is a fraction of sunlight, it can be damaging to living organisms. All of these are forms of energy in the electromagnetic spectrum.
    • 5: Flame Tests and Atomic Spectra (Experiment)
      The objectives of this lab are to: Perform flame tests of metal cations in order to observe their characteristic colors, Perform calculations to determine the frequency and energy of the emitted photons. Relate these results to the types of electronic transitions occurring in these elements. Observe and understand line emission spectra of atoms using gas-discharge tubes. Practice writing electron configurations for these (and other) elements.
    • 6: Lewis Structures and Molecular Shapes (Experiment)
      Non-metal atoms bond covalently, resulting in the formation of either neutral molecules or polyatomic ions. A covalent bond is formed when non-metal atoms share their valence electrons, which they do in order to achieve filled valence orbitals like their nearest noble gas neighbor. This means that most bonded non-metal atoms will acquire a total of eight valence electrons via the sharing process – often referred to as the octet rule.
    • 7: Electrical Conductivity of Aqueous Solutions (Experiment)
      Electrical conductivity is based on the flow of electrons. Highly ionized substances are strong electrolytes. Strong acids and salts are strong electrolytes because they completely ionize (dissociate or separate) in solution. The ions carry the electric charge through the solution thus creating an electric current. The current, if sufficient enough, will light one or both LEDs on a conductivity meter, shown at right.
    • 8: Acid, Bases and pH (Experiment)
      The objectives of this laboratory are: Set up and show how to use a pH indicator Determine the pH of common solutions Understand pH differences of acids and bases Learn to use a laboratory pH meter Understand relationship between pH and H+ ion concentration
    • 9: Single Replacement Reactions and Batteries (Experiment)
      During a chemical reaction both the form and composition of matter are changed. Old substances are converted to new substances, which have unique physical and chemical properties of their own.
    • 10: Double Replacement Reactions (Experiment)
      Reactions that can be classified as double replacements include precipitation reactions, neutralization reactions and gas forming reactions.
    • 11: Synthetic Polymers and Plastics (Experiment)
      The word “polymer” means “many units”. A polymer can be made up of many repeating units, which are small monomer molecules that have been covalently bonded. Figure 1 (from Chemistry in Context) shows a single monomer, and a polymer made of identical monomers linked together. A polymer can contain hundreds of monomers, totaling thousands of atoms.  Plastic is a type of synthetic polymer. Currently, more than 60,000 plastics are manufactured for industrial and commercial purposes.
    • 12: Making Soap - Saponification (Experiment)
      Soap making has remained unchanged over the centuries. The ancient Roman tradition called for mixing rain water, potash and animal tallow.