• Two extremely important principles in electric circuits were codified by Gustav Robert Kirchhoff in the year 1847, known as Kirchhoff’s Laws. His two laws refer to voltages and currents in electric circuits, respectively. Kirchhoff’s Voltage Law states that the algebraic sum…

  • In addition to Ohm’s Law, we have a set of rules describing how voltages, currents, and resistances relate in circuits comprised of multiple resistors. These rules fall neatly into two categories: series circuits and parallel circuits. The two circuit types are shown here, with…

  • To review, voltage is the measure of potential energy available to electric charges. Current is the uniform drifting of electric charges in response to a voltage. We can have a voltage without having a current, but we cannot have a current without first having…

  • Since we often use electricity to convey energy from one location to another, it is important to be able to quantify and calculate the rate at which energy is delivered by an electric circuit. The rate at which energy transfers from one…

  • By definition, a source is a device delivering energy into a system, while a load is a device extracting energy from a system. Examples of typical electrical sources include generators, photovoltaic cells, thermopiles, and primary-cell batteries. These devices create electrical voltage, which in turn…

  • Current is the name we give to the motion of electric charges from a point of high potential to a point of low potential. All we need to form an electric current is a source of potential (voltage) and some electric…

  • Voltage is the amount of specific potential energy available between two points in an electric circuit. Potential energy is energy that is potentially available to do work. Looking at this from a classical physics perspective, potential energy is what we accumulate when we…

  • Hydrogen ion activity in aqueous (water-solvent) solutions is a very important parameter for a wide variety of industrial processes. A number of reactions important to chemical processing are inhibited or significantly slowed if the hydrogen ion activity of a solution…

  • 3.11 Ions in liquid solutions Many liquid substances undergo a process whereby their constituent molecules split into positively and negatively charged ion pairs, the positively-charge ion called a cation and the negatively-charged ion called an anion37 . Liquid ionic compounds38 split into ions completely or nearly completely, while…

  • A chemical reaction resulting in a net release of energy is called exothermic. Conversely, a chemical reaction requiring a net input of energy to occur is called endothermic. The relationship between chemical reactions and energy exchange corresponds to the breaking or making…

  • Stoichiometry is the accounting of atoms before and after a chemical reaction. It is an expression of the Law of Mass Conservation, in that elements are neither created nor destroyed in a chemical reaction, and that mass is an intrinsic property of…

  • Sample sizes of chemical substances are often measured in moles. One mole of a substance is defined as a sample having 6.022 × 1023 (Avogadro’s number) molecules25 . This number is not arbitrary – it was chosen26 such that 1 mole of carbon-12 (6.022 × 1023 individual 12C atoms together…

  • Most of these formulae appear in molecular chemical form rather than structural form. For example, ethanol appears here as C2H6O rather than C2H5OH. Also, the entries for fructose and glucose are identical (C6H12O6) despite the two compounds having different structures. This means…

  • Much of our knowledge about atomic structure comes from experimental data relating the interaction between light and atoms of the different elements. Light may be modeled as an electromagnetic wave, consisting of an oscillating electric field and an oscillating magnetic field. Like…

  • Earlier in this chapter you were shown a model of a nitrogen atom with a dense nucleus (comprised of protons and neutrons) surrounded by electrons whirling around like satellites around a planet. While there are some useful features of this…

Join 900+ subscribers

Stay in the loop with everything you need to know.

Sign up