Thermochemistry Flashcards
(24 cards)
What is thermochemistry?
The study of energy involved in chemical reactions.
What does the law of conservation of energy state? (1)
The total energy of the universe is constant.
How is the system different from the surroundings?
The system is defined as the part of the universe that is being studied and observed. (Reactants and products)
The surroundings are everything else in the universe.
That is the first law of thermodynamics?
Any change in the energy of a system is accompanied by an equal and opposite change in the energy of the surroundings.
What is an open system? Give an example.
Both energy and matter may be exchanged between an open system and its surroundings.
Example: a reaction in an open beaker.
What is a closed system? Give an example.
Matter cannot move between the system and surroundings. Energy can be transferred between a closed system and its surroundings.
Example: a reaction in a stoppered Erlenmeyer flask.
What is an isolated system?
It is completely undulate from its surroundings. Neither matter nor energy is exchanged between an isolated system and its surroundings.
What is kinetic energy?
Energy of motion.
What is potential energy?
Energy that is stored.
What SI unit is used for both kinetic and potential energy?
Joule (J).
What does temperature measure?
The average kinetic energy of the particles that make up a substance or system.
What is heat?
Heat, q, refers to the transfer of kinetic energy between objects with different temperatures.
What is specific heat capacity?
The quantity of energy that is required to change one gram of the substance by one degree Celsius.
What does specific heat capacity reflect on?
How well the substance can store energy.
What does heat capacity (C) relate to?
The heat of a given sample, object, or system to its change in temperature.
What does enthalpy change refer to?
The potential energy change if a system during a process such as a chemical reaction or a physical change.
What are enthalpy changes measured in?
kJ/mol.
Are chemical bonds sources of kinetic or potential energy?
Potential energy (stored).
Breaking a bind is a process that ______ energy.
Requires.
Creating a bind is a process that ________ energy.
Releases.
Endothermic reactions have a net _________ of energy.
Absorption.
Exothermic reactions have a net _________ of energy.
Release.
What is the standard molar enthalpy of formation?
The quantity of energy that is absorbed or released when one mol of a compound is formed directly from its elements in their standard states.
The study of energy and energy transfer is know as _______.
Thermodynamics.
