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Mastering Electrical Conductivity in Chemistry
Dive into the world of electrical conductivity in chemistry. Understand what substances conduct electricity, how to test for conductivity, and the science behind ionic compounds' conductive properties.

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Now Playing:Electrical conductivity – Example 0a
Intros
  1. Conducting electricity
  2. Conducting electricity
    What is electrical conductivity?
  3. Conducting electricity
    Factors affecting electrical conductivity.
Examples
  1. Recall the factors that affect electrical conductivity.
    A student sets up a circuit containing a large lightbulb, using electrodes placed in a solution of different compounds dissolved in water. The solutions are measured to be all be the same concentration. The circuit was switched on and the state of the lightbulb was recorded.
    1. Some results shows the lightbulb not glowing at all. What does this tell us about the solution?

    2. In one solution, the bulb glowed weakly. The student then decided to increase the concentration tenfold by adding ten times more solute (the solution is still unsaturated). Describe and explain what happened to the lightbulb after doing this.

    3. In one experiment, the student did not use a solution, but instead crystals of an ionic compound. The lightbulb did not glow at all. Using standard laboratory equipment, suggest two things that the student could do to make the light bulb glow.

Introduction to solution chemistry and solubility
Jump to:NotesConceptFAQsPrerequisites
Notes
In this lesson, we will learn:
  • A definition of electrical conductivity.
  • Why some compounds are conductors of electricity and others are not.
  • How solutions affect electrical conductivity.
  • How to recognize conductors of electricity by their chemical formula.

Notes:
  • Electrical conductivity is the rate of flow of electric charge. It is the ability of any substance to allow electric charge to flow throughout its structure.
    "Electric charge" is just moving electrons – if electrons can flow freely through a substance as its structure allows them to, then the substance can conduct electricity.

  • This is important for chemists because solutions can have very different properties to the individual solvent or solutes they are made of – ionic compounds can't conduct in the solid state but they can when dissolved or melted.

  • Ionic compounds are able to conduct electricity in solution because when ionic compounds dissolve, they break up into their separate ions (called dissociation). These charged particles allow any electric charge (read: electrons) free movement. For example when sodium chloride is dissolved (NaCl):

    • NaCl → Na+(aq) + Cl-(aq)

    Remember that when dissolved in water, we say a chemical is in the aqueous phase. If a compound is insoluble in water it should not be referred to as being aqueous.

  • As with any chemical property, different compounds dissociate in solution more or less than others – some might only show 1% of molecules dissociating, others over 90%. This will affect how well electricity is conducted as the molecules must be in dissociated ionic form for charge to be transferred.
    • Experiments can be performed to show this, where circuits are made using electrodes in a solution with light bulbs in the circuit:
      • One or more bulbs of different power consumption (watts) are put in the electric circuit and show different brightness with different solutions tested, which have different conductivity depending on the solute/solvent mixture.
      • The brighter the bulb(s) glow, the better the solution conducts electricity.

  • Phase is important to electrical conductivity – both aqueous and the liquid phase allow free flowing particles including electric charge. Liquid and aqueous states allow the molecules to dissociate into ions and for those ions to have the energy to move freely!
    • Experiments like those above with solutions can be done with different phases to find this out:
      • Crystals and solid ionic compounds do not conduct electricity and the bulbs do not glow.
      • Once dissolved or heated to a molten state the bulbs begin glowing.

  • Another issue affecting conductivity is concentration. The more concentrated a solution is, the greater the conductivity measured (if the solute is a conductor in solution). This is because the higher the concentration of the solute, the more ions will be available to carry electric charge.

  • Generally speaking, the following rules can be followed to determine if a substance will conduct electricity:

    • Substance (state)

    Conducts electricity?

    Metal (solid)

    Yes

    Metal (melted)

    Yes

    Acid or base/alkali (solid)

    No

    Acid or base/alkali (solution)

    Yes

    Ionic compound (solid)

    No

    Ionic compound (melted)

    Yes

    Ionic compound (solution)

    Yes

    Organic acids (solution)

    Yes

    None of the above

    No


  • Using the table above and knowledge of ions helps us think about what chemicals and substances are conductors of electricity – look for:
    • Metals (their structures contain delocalized electrons themselves)
    • Mineral acids and bases (inorganic compounds that have H or OH groups)
    • Other compounds that will dissociate into ions when dissolved (organic acids and their metal salts)
    What these all have in common is that charged particles are present or generated in all of them.

  • If we need solutions where charged, ion-forming compounds are soluble, what effect could this have on the solvents you can use to make conducting solutions? Conducting solutions are made with polar solvents – a nonpolar solvent won't dissolve polar, ion-forming solutes!
Concept

Introduction to Electrical Conductivity in Chemistry

Welcome to our exploration of electrical conductivity in chemistry! This fascinating concept is crucial for understanding how materials interact with electricity. Electrical conductivity refers to a substance's ability to allow the flow of electric current. In chemistry, we often examine how different solutions and materials conduct electricity. The conductivity meaning in chemistry extends beyond just metals; it includes ionic solutions and even some non-metallic substances. Our introduction video will visually demonstrate this concept, making it easier to grasp. You'll see how conductivity varies among different materials and solutions, which is key to many chemical processes. Understanding conductivity chemistry definition is essential for various applications, from battery technology to water quality testing. As we dive deeper, you'll discover how this property relates to chemical bonding and ion mobility. Ready to explore this electrifying topic? Let's get started!

FAQs

Here are some frequently asked questions about electrical conductivity in chemistry:

1. What is electrical conductivity in chemistry?

Electrical conductivity in chemistry refers to a substance's ability to allow the flow of electric current. It measures how easily electric charge can pass through a material. In chemical terms, it's related to the presence of mobile charged particles, such as ions in solutions or free electrons in metals.

2. What substances conduct electricity?

Several types of substances can conduct electricity:

  • Metals (e.g., copper, aluminum, silver)
  • Aqueous solutions of ionic compounds
  • Molten ionic compounds
  • Some non-metallic elements (e.g., graphite)
  • Plasma
The best conductors are typically metals due to their abundance of free electrons.

3. Why do some substances conduct electricity while others don't?

Substances conduct electricity when they have mobile charge carriers. In metals, these are free electrons. In solutions, these are ions. Insulators lack these mobile charge carriers. The atomic or molecular structure of a substance determines whether it has these mobile charges. For example, metals have a "sea" of free electrons, while in ionic solutions, the dissociated ions can carry charge.

4. How is electrical conductivity measured in chemistry?

Electrical conductivity is typically measured using a conductivity meter. This device applies a voltage across a sample and measures the resulting current. The conductivity is then calculated using Ohm's law and the cell constant of the measuring device. The standard unit of conductivity is Siemens per meter (S/m).

5. What factors affect electrical conductivity in solutions?

Several factors influence the electrical conductivity of solutions:

  • Concentration of ions: Higher ion concentration generally increases conductivity
  • Temperature: Usually, higher temperatures increase conductivity
  • Nature of the solute: Strong electrolytes produce more ions and higher conductivity
  • Nature of the solvent: Solvents that facilitate ion dissociation lead to higher conductivity
  • Size and charge of ions: Smaller, more highly charged ions typically result in higher conductivity
Understanding these factors is crucial for applications in water quality testing, electrochemistry, and materials science.

Prerequisites

Understanding electrical conductivity is a fundamental concept in physics and electrical engineering. While there are no specific prerequisite topics provided for this subject, it's important to recognize that a solid foundation in basic scientific principles can greatly enhance your comprehension of electrical conductivity. This article will explore the importance of related concepts and how they contribute to a deeper understanding of electrical conductivity.

Electrical conductivity is a measure of a material's ability to allow the flow of electric current. To fully grasp this concept, it's beneficial to have a basic understanding of atomic structure and electron behavior. These foundational principles help explain why some materials are better conductors than others.

A key aspect of electrical conductivity is the movement of electrons through a material. This process is closely related to the concept of electric current, which describes the flow of electric charge. Having a clear understanding of electric current and its properties can significantly enhance your ability to comprehend electrical conductivity.

Another important factor in electrical conductivity is the concept of resistance. Resistance is the opposition to the flow of electric current in a material. Understanding the relationship between conductivity and resistance is crucial for analyzing electrical systems and circuits.

The study of electrical conductivity also involves exploring different types of materials, such as conductors, insulators, and semiconductors. Knowledge of material properties and their atomic structures can provide valuable insights into why certain substances conduct electricity better than others.

Temperature plays a significant role in electrical conductivity, as it affects the movement of electrons within a material. Understanding the principles of thermodynamics and how temperature influences atomic behavior can help explain the temperature dependence of electrical conductivity.

In practical applications, electrical conductivity is often studied in the context of circuits and electrical systems. Having a basic understanding of circuit theory and Ohm's law can greatly enhance your ability to apply conductivity concepts to real-world scenarios.

While not directly listed as prerequisites, familiarity with mathematical concepts such as algebra and basic calculus can be beneficial when dealing with more advanced aspects of electrical conductivity. These mathematical tools are often used to describe and analyze conductivity in quantitative terms.

In conclusion, while there are no specific prerequisite topics listed for electrical conductivity, a strong foundation in basic physics, chemistry, and mathematics can significantly enhance your understanding of this important concept. By building a comprehensive knowledge base in related areas, you'll be better equipped to explore the intricacies of electrical conductivity and its applications in various fields of science and engineering.