Presentation on theme: "TEKS Objective (6) The student knows the impact of energy transformations in everyday life. The student is expected to: (E) measure the thermal and electrical."— Presentation transcript:
TEKS Objective (6) The student knows the impact of energy transformations in everyday life. The student is expected to: (E) measure the thermal and electrical conductivity of various material and explain the results.
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Is NaCl a conductor? NaCl does not conduct electricity as it is. NaCl is an ionic compound and both the Na + and the Cl - are strongly attracted to each other by electrostatic action. The flow of charge is not possible.
Is 5% NaCl soltion a conductor? Yes, water molecules separate the Na + and the Cl - ions. This makes them very mobile. The mobility is enhanced when the two electrodes in the form of anode and cathode are inserted in the salt solution. This type of solution is called an electrolyte.
Ionic Bonds An ionic bond is typically formed between a metal and a non-metal. Consequently, the non-metal is "stronger" than the metal, and can steal electrons very easily from the metal. This results in the metal becoming a cation, and the non-metal becoming an anion. An ionic bond is the resulting attraction for an anion and a cation after an electron is transferred from the metal to the non-metal.
Do covalent compounds conduct electricity? A covalent bond does not allow electrons to move freely within the body of the object. A covalent bond is typically formed by two non-metals. Neither atom is "strong" enough to steal electrons from the other. Therefore, the atoms must share the electrons.
How does electricity flow in metal? In metals, free electrons carry the current. In metal wire, all the atoms share the electrons in their outermost electron shell and these electrons are free to move anywhere within the wire.
What is the purpose of the battery? The battery supplies electrons which flow from the negative end where there are many electrons to the positive end where there are few electrons.
Learning Goal In this investigation students learn that the ability of a material to conduct an electric current is dependent upon: The presence of charged particles The ability of these charged particles to move