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- https://chem.libretexts.org/Courses/Westfield_State_University/Chem0103_Chemistry_of_the_Life_Sciences_(Theis)/01%3A_Atoms_and_compounds/1.06%3A_Extras/1.6.04%3A_Basic_Concepts_of_Chemical_Bonding_(GenChem_Brown)/1.6.4.03%3A_Covalent_BondingThe strength of a covalent bond depends on the overlap between the valence orbitals of the bonded atoms. Bond order is the number of electron pairs that hold two atoms together. Single bonds have a bo...The strength of a covalent bond depends on the overlap between the valence orbitals of the bonded atoms. Bond order is the number of electron pairs that hold two atoms together. Single bonds have a bond order of one, and multiple bonds with bond orders of two (a double bond) and three (a triple bond) are quite common. In closely related compounds with bonds between the same kinds of atoms, the bond with the highest bond order is both the shortest and the strongest.
- https://chem.libretexts.org/Courses/Lubbock_Christian_University/LCU%3A_CHE_1305_-_Introductory_Chemistry/11%3A_Energy/11.6%3A_Phase_ChangesFusion, vaporization, and sublimation are endothermic processes, whereas freezing, condensation, and deposition are exothermic processes. Changes of state are examples of phase changes, or phase trans...Fusion, vaporization, and sublimation are endothermic processes, whereas freezing, condensation, and deposition are exothermic processes. Changes of state are examples of phase changes, or phase transitions. All phase changes are accompanied by changes in the energy of a system. Changes from a more-ordered state to a less-ordered state (such as a liquid to a gas) are endothermic. Changes from a less-ordered state to a more-ordered state (such as a liquid to a solid) are always exothermic.
- https://chem.libretexts.org/Courses/Lansing_Community_College/LCC%3A_Chem_151_-_General_Chemistry_I/Text/09%3A_Basic_Concepts_of_Chemical_Bonding/9.08%3A_Strength_of_Covalent_BondsBond order is the number of electron pairs that hold two atoms together. Single bonds have a bond order of one, and multiple bonds with bond orders of two (a double bond) and three (a triple bond) are...Bond order is the number of electron pairs that hold two atoms together. Single bonds have a bond order of one, and multiple bonds with bond orders of two (a double bond) and three (a triple bond) are quite common. The bond with the highest bond order is both the shortest and the strongest. In bonds with the same bond order between different atoms, trends are observed that, with few exceptions, result in the strongest single bonds being formed between the smallest atoms.
- https://chem.libretexts.org/Courses/Los_Angeles_Trade_Technical_College/LATTC_Hybrid_Chem_51/07%3A_Energy_and_Chemistry/7.3%3A_Enthalpy_and_Chemical_ReactionsEvery chemical reaction occurs with a concurrent change in energy. The change in enthalpy equals heat at constant pressure. Enthalpy changes can be expressed by using thermochemical equations. Enthalp...Every chemical reaction occurs with a concurrent change in energy. The change in enthalpy equals heat at constant pressure. Enthalpy changes can be expressed by using thermochemical equations. Enthalpy changes are measured by using calorimetry.
- https://chem.libretexts.org/Courses/University_of_Missouri/MU%3A__1330H_(Keller)/11%3A_Liquids_and_Intermolecular_Forces/11.4%3A_Phase_ChangesFusion, vaporization, and sublimation are endothermic processes, whereas freezing, condensation, and deposition are exothermic processes. Changes of state are examples of phase changes, or phase trans...Fusion, vaporization, and sublimation are endothermic processes, whereas freezing, condensation, and deposition are exothermic processes. Changes of state are examples of phase changes, or phase transitions. All phase changes are accompanied by changes in the energy of a system. Changes from a more-ordered state to a less-ordered state (such as a liquid to a gas) are endothermic. Changes from a less-ordered state to a more-ordered state (such as a liquid to a solid) are always exothermic.
- https://chem.libretexts.org/Courses/Los_Angeles_Trade_Technical_College/DMA_Chem_51_Su_19/2%3A_Beginning_Chemistry_(Ball)/07%3A_Energy_and_Chemistry/7.4%3A_Enthalpy_and_Chemical_ReactionsEvery chemical reaction occurs with a concurrent change in energy. The change in enthalpy equals heat at constant pressure. Enthalpy changes can be expressed by using thermochemical equations. Enthalp...Every chemical reaction occurs with a concurrent change in energy. The change in enthalpy equals heat at constant pressure. Enthalpy changes can be expressed by using thermochemical equations. Enthalpy changes are measured by using calorimetry.
- https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Beginning_Chemistry_(Ball)/07%3A_Energy_and_Chemistry/7.04%3A_Enthalpy_and_Chemical_ReactionsEvery chemical reaction occurs with a concurrent change in energy. The change in enthalpy, a kind of energy, equals heat at constant pressure. Enthalpy changes can be expressed by using thermochemical...Every chemical reaction occurs with a concurrent change in energy. The change in enthalpy, a kind of energy, equals heat at constant pressure. Enthalpy changes can be expressed by using thermochemical equations. Enthalpy changes are measured by using calorimetry.
- https://chem.libretexts.org/Courses/Providence_College/Organic_Chemistry_I/08%3A_Substitution_Reactions/8.03%3A_The_Basics_of_Determining_MechanismThe mechanism is protonation of the alkene (πC−C = HOMO) at the less highly substituted carbon atom of the alkene to form a stable carbocation, which then gets trapped by a nucleophile (followe...The mechanism is protonation of the alkene (πC−C = HOMO) at the less highly substituted carbon atom of the alkene to form a stable carbocation, which then gets trapped by a nucleophile (followed by deprotonation, if applicable). What this means is that the rate of the reaction is dependent only on the presence of one molecule in the rate determining step, hence 1 st order.
- https://chem.libretexts.org/Courses/Williams_School/Chemistry_IIA/02%3A_Thermochemistry/2.02%3A_The_First_Law_of_ThermodynamicsThe first law of thermodynamics states that the energy of the universe is constant. The change in the internal energy of a system is the sum of the heat transferred and the work done. At constant pres...The first law of thermodynamics states that the energy of the universe is constant. The change in the internal energy of a system is the sum of the heat transferred and the work done. At constant pressure, heat flow (q) and internal energy (U) are related to the system’s enthalpy (H). The heat flow is equal to the change in the internal energy.
- https://chem.libretexts.org/Bookshelves/General_Chemistry/ChemPRIME_(Moore_et_al.)/03%3A_Using_Chemical_Equations_in_Calculations/3.06%3A_ThermochemistryWhen a chemical reaction occurs, there is usually a change in temperature of the chemicals themselves and of the beaker or flask in which the reaction is carried out. If the temperature increases, the...When a chemical reaction occurs, there is usually a change in temperature of the chemicals themselves and of the beaker or flask in which the reaction is carried out. If the temperature increases, the reaction is exothermic—energy is given off as heat when the container and its contents cool back to room temperature. (Heat is energy transferred from one place to another solely because of a difference in temperature.)
- https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/02%3A_Matter_and_Change/2.13%3A_Chemical_ReactionThis page explains chemical reactions as processes where reactants transform into products through bond changes, occurring in laboratories and daily life. It outlines different reaction types: synthes...This page explains chemical reactions as processes where reactants transform into products through bond changes, occurring in laboratories and daily life. It outlines different reaction types: synthesis, decomposition, replacement, and combustion. It highlights energy dynamics, distinguishing between exothermic reactions (releasing more energy) and endothermic reactions (absorbing more energy). These concepts are essential for understanding chemistry.
