Exothermic and Endothermic Reactions Flashcards
What is an exothermic reaction?
Energy in the form of heat is released into the surroundings, so the solutions feel hot.
What is an endothermic reaction?
Energy in the form of heat is taken into the bonds, so the solutions feel cold.
Examples of exothermic reactions in everyday life
Burning charcoal, burning a candle and a firework exploding
Examples of endothermic reactions in every day life
Boiling a kettle and melting ice
Do you have to put heat in or get heat out for boiling and melting?
Heat in
Do you have to put heat in or get heat out for burning and exploding?
Get heat out
What does 🔺H mean and when do we use it?
Change in enthalpy (thermal energy). We use it to identify what kind of reaction a reversible reaction is.
What does enthalpy mean?
It is the technical term for energy
Where is enthalpy stored?
In the bonds (in the form of chemical energy)
What kind of reaction is breaking bonds?
Breaking bonds is an endothermic reaction because breaking something requires energy
What kind of reaction is making new bonds?
Making new bonds is an exothermic reaction
Why does not all energy go into making new bonds?
The other energy is desperate into the surroundings as heat energy
If 🔺H = -, what kind of reaction is it?
It is an exothermic reaction
In an exothermic reaction, is the energy of the products higher than the energy of the reactants or lower?
The energy of the products is lower than the energy of the reactants and energy is given off into the surroundings as heat.
In an endothermic reaction, is the energy of the products higher than the energy of the reactants or lower?
The energy of the products is higher than the energy of the reactants. Energy in the form of heat is taken into the surroundings.
What does an energy level diagram for an endothermic reaction look like?
Products |———– | | | Reactants | 🔺H = + ————| ————————> Progress of the reaction
