Exothermic & Endothermic Reactions Flashcards
(19 cards)
what is the Law of Conservation of Mass?
Matter can neither be created nor destroyed in a chemical reaction.
The atoms are only rearranged.
What is the Law of Conservation of Energy?
a closed system (a system that isolated from its surroundings) the total energy of the system is conserved.
for a chemical reaction to occur…
energy is required
what is engery required to do in a chemical equation?
break the bonds between the reactant atoms
form new bonds between atoms in the products
different reacions may need…
different amounts of energy
some will occur at…
room temp but others need a ‘spark’.
what is an example of a chemical reaction that occurs at room temp?
hydroxide reacts with hydrochloric acid to produce sodium chloride and water, at room temperature:
NaOH(aq) + HCl(aq) —–> NaCl(aq) + H2O(l)
what is enthalpy?
the heat content of a system) is the energy required for a substance (the reactants) to undergo a change.
what is the symbol for enthalpy?
ΔH
what does Δ stand for and what does it mean?
delta and means difference/ change in
how is Enthalpy is calculated?
ΔH = ΔHproducts – ΔHreactants
what are Exothermic reactions?
Exothermic chemical reactions are reactions that produce energy, (release heat = feel hot) which moves into the environment, during the reaction.
after the rearrangement in Exothermic reactions there is…
less energy is stored in the bonds
what is the general eqaution for an Exothermic reactions?
reactants –> products + heat energy
what is an example of Exothermic reactions?
cellular respiration
C6H12O6 + 6 O2 —> 6 CO2 + 6 H2O + energy (ATP)
what are endo thermic reactions?
reactions that absorb energy (absorb heat = feel cold)
after the rearrangment in endothermic reactions…
more energy is stored in the bonds of the products.
what is the general equation for endothermic reactions?
reactants + heat energy -> products
what is an example of a endothermic reaction?
6 CO2 + 6 H2O —> (on top of arrow is sunlight) C6H12O6 + 6 O2
