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25 Cards in this Set
- Front
- Back
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Define energy.
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The capacity to do work, generate heat and/or generate electricity.
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What are the two laws of thermodynamics?
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1. Energy can be converted into different forms, but the total energy of a system is constant.
2. With every energy conversion, energy is always lost as heat. |
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What are the 4 primary sources of energy?
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Chemical, nuclear, solar and geological.
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Name the 4 kinds of energy changes in descending order in how much energy they involve.
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Nuclear, chemical, phase, and temperature.
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What is kinetic energy? What does an increase in kinetic energy cause?
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The energy of motion of particles. An increase in kinetic energy results in an increase in temperature.
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What is heat?
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The transfer of thermal energy.
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What are the three types of kinetic energy?
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Vibrational motion, rotational motion and translational motion.
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Define heat capacity.
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The heat required to change the temperature of a unit mass of a substance by 1 degree celsius.
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True or false, phase changes always involve a change in kinetic energy.
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False, phase changes always involve a change in potential energy.
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Melting, vaporization and sublimation are all ___________ reactions.
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endothermic
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What types of phase changes are exothermic?
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Freezing, condensation and deposition.
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What is enthalpy?
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The total kinetic and potential energy of a chemical system under a constant pressure and temperature.
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True or false, during a phase change kinetic energy remains constant.
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True
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What is molar enthalpy?
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The enthalpy change per mole of a substance.
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What is colorimetry?
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A technological process of measuring energy change using an isolated system.
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Who are your best friends in Chemistry 30?
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Oxidation numbers, P-R, HL=HG, and P/R.
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What is chemical change?
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A transformation involving an energy change in which one substance is converted into another substance.
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What is the heat of reaction?
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The enthalpy change of a reaction referring to changes in potential energy.
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What does a negative heat of reaction mean?
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The reaction is exothermic.
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What is bond energy?
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The energy required to break a chemical bond or the energy released when a bond is formed.
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What is the activation energy?
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The energy required to pull apart the atoms in the reactants, always higher than the energy contained in the reactants and the products.
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What happens to the activation energy for the reaction when a catalyst is added?
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A catalyst acts to lower the activation energy.
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What is Hess's Law?
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If two or more thermochemical equations are added to give a final equation, then the enthalpies can be added to give the enthalpy for the final equation.
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What is heat of formation?
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The changes in potential energy that occur when compounds are formed from their elements.
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What is an indirect measure of the stability of a compound?
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Heats of formation can indicate the stability of a compound. The more exothermic the formation, the more stable the compound.
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