chemistry
Terms
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- molar mass
- The mass of one mole of atoms, molecules or formula units of the compound or element.
- average atomic mass
- The average of the atomic masses of each of an element's isotopes, weighted by natural abundance.
- system
- The substance or substances under study in which a change occurs
- stoichiometry
- Quantitative relationship between reactants and products and their component atoms in chemical reactions.
- enthalpy
- A thermodynamic state function. It is the heat content of a chemical system.
- light energy
- Kinetic energy due to photon movement
- first law of thermodynamics
- Energy may be converted from one form to another, but the total quantity of energy remains constant.
- heat
- The energy that flows into or out of a system because of a difference in temperature between the system and its surroundings.
- specific heat capacity
- The unique heat capacity of a substance; also called specific heat; amount of heat needed to raise the temperature of a 1 g sample of the substance by 1 Kelvin
- thermochemical equation
- The balanced chemical equation and the enthalpy change of the chemical reaction
- molar mass
- The mass of one mole of atoms, molecules, or formula unit of the compound or element.
- mechanical energy
- Kinetic energy due to movement of objects.
- Avogadro's number
- The number of atoms or molecules in a mole — 6.0221 X 1023
- joule
- The SI unit for energy, named after physicist James Prescott Joule
- surroundings
- Everything in the vicinity of a thermodynamic system
- kinetic energy
- The energy associated with motion, equal to one-half the mass of the moving object times its velocity squared.
- standard state
- For a pure substance, the most stable form of the substance at 1 atm and a specified temperature, usually 25°C: for a gas, 1 atm; for a solution, concentration of 1 molar.
- dimensional analysis
- A method of analyzing and solving problems by using units of measurement
- coffee cup calorimeter
- A type of constant-pressure calorimeter
- empirical formula
- A chemical formula that shows the relative number of each type of atom in a molecule, using the smallest possible set of integers
- absolute zero
- The coldest temperature, 0 Kelvin, that can be reached. It is the hypothetical temperature at which all molecular motion stops.
- work
- A transformation of energy that moves matter in an organized way against an opposing force.
- mole
- The amount of a substance that contains as many particles as there are atoms in exactly 12 grams of carbon-12.
- combustion analysis
- A method used to determine the composition of compounds containing the elements carbon, hydrogen, and occasionally nitrogen.
- molarity
- The concentration of a solution, in moles of solute per liter of solution
- exothermic reaction
- A chemical reaction that releases heat into the surroundings
- energy
- The capacity to do work or to produce heat
- endothermic reaction
- A chemical reaction that absorbs heat from the surroundings
- mole ratio
- Shows the quantity relationship between two species
- heat energy
- The energy due to the motion of the atoms or molecules within a system
- percent yield
- The actual yield divided by the theoretical yield multiplied by 100
- theoretical yield
- The maximum amount of product that can be obtained from given amounts of reactants in a chemical reaction.
- absolute temperature
- The temperature scale on which the coldest possible temperature is zero. The unit of absolute temperature is Kelvin.
- enthalpy change
- Symbolized by ΔH, it is the heat absorbed or released by a system at constant pressure.
- chemical potential energy
- A type of potential energy due to energy stored in the bonds of chemicals or molecules.
- formula mass
- The sum of the atomic masses of all the atoms in a chemical formula
- mass percentage
- The mass of a given element in a compound divided by the total mass of the compound and multiplied by 100.
- Hess's law
- The enthalpy change of an overall reaction is equal to the sum of the enthalpy changes of its individual steps.
- calorimeter
- Device used to measure the heat absorbed or released in a chemical reaction
- gravitational potential energy
- A type of positional potential energy due to the Earth's gravity
- heat capacity
- The amount of heat required to raise the temperature of a specified amount of a substance by 1°C or 1 K.
- heat of solution
- Heat associated with the dissolution of a solute in a solvent
- quantitative chemistry
- A branch of chemistry that focuses on quantities of substances in a chemical reaction.
- conduction
- The transfer of heat through direct contact of materials of different temperature
- Thermochemistry
- The branch of thermodynamics that is concerned with the study of energy changes that accompany chemical reactions.
- law of conservation of energy
- Energy may be converted from one form to another, but the total quantity of energy remains constant.
- standard formation reaction
- A reaction in which 1 mole of a substance is formed from its component elements in their standard states.
- actual yield
- The amount of product obtained in a chemical reaction.
- standard enthalpy change
- The enthalpy change for a reaction where all of the substances are in their standard states. It has the symbol ΔH°.
- thermodynamics
- The study of energy and its transformations
- thermal energy
- Kinetic energy due to atomic or molecular motion
- mass
- The quantity of matter in an object
- electrical energy
- Kinetic energy due to electron movement.
- percent composition
- The percent by mass of the constituent elements of a compound
- atomic mass unit
- A unit equal to one twelfth the mass of a carbon-12 atom.
- sound energy
- Kinetic energy due to molecular vibration
- potential energy
- The energy an object has due to its composition or its position relative to a force
- calorimetry
- The measurement of heat flow into or out of a system as the result of a chemical reaction or physical process.
- calorie
- The amount of energy needed to raise the temperature of 1 g of water by 1°C. It is equal to 4.184 joules.
- weight
- The force that an object exerts as a result of gravity
- limiting reagent
- The reactant that is completely consumed in a chemical reaction; determines the total amount of product that can be formed.
- molecular mass
- The sum of the masses of all the atoms in a molecule
- constant-pressure calorimeter
- A calorimeter where the contents remain at atmospheric pressure
- convection
- The transfer of heat due to molecular motion in currents within fluids
- standard enthalpy of formation
- Enthalpy change for a standard formation reaction
- combustion reaction
- An exothermic reaction between a compound and molecular oxygen
- Calorie
- The amount of energy equal to 1000 calories, or 4.184 x 103 joules
- heat of reaction
- The heat change in a chemical reaction