Chem chemical change p2 Flashcards
thermodynamics
the study of heat or flow of energy in chemical reactions
enthalpy (H)
describes the heat content of a system
enthalpy change (ΔH)
the heat added to a system under conditions of standard pressure
exothermic reaction
a chemical reaction during which heat energy is transferred to the surroundings
exothermic reaction symbols
ΔH < 0
endothermic reaction
a chemical reaction during which heat energy is taken from the surroundings
endothermic reaction symbols
ΔH > 0
activation energy (Eᴀ)
the minimum energy required to start a chemical reaction through initial bond breaking, allowing new bonds to be made
unit activation energy is measured in
kJ.mol^-1
activated complex
an intermediate state in a chemical reaction that is formed while bonds are breaking and new bonds are forming
heat
transfer of energy between the system and its surroundings
BrØnsted-Lowry definition of an acid
a proton (H^+) donor
BrØnsted-Lowry definition of bases
a proton (H^+) acceptor
general reaction of the BrØnsted-Lowry theory
HA + B → (BH^+) +A^-
monoprotic acids
acids that can only donate one proton
polyprotic acids
acids that can donate more than 1 proton
diprotic acids
acid that can only donate 2 protons
triprotic acid
acid that can donate 3 protons
Arrhenius’s definition of an acid
a compound that produces hydrogen ions (H^+) in an aqueous solution
Arrhenius’s definition of a base
produces hydroxide ions (HO^-) in a aqueous solution
arrhenius theory’s general equation
(H^+) + (OH^-) → H2O
conjugate acid-base pair
acid and base related by a proton transfer in an acid-base reaction
ampholyte
a substance that can act as either an acid or a base depending on what it is reacting with
oxidation
the loss of electrons
reduction
is the gain of electrons
oxidation number
the oxidation number of an element is a number assigned to each element in a compound in order to keep track of the movement of electrons during a reaction
