DF1 - Thermochemistry Flashcards
Getting energy from fuels
Define ‘thermochemistry’.
The study of energy and heat associated with chemical reactions
Define ‘exothermic’.
A reaction that gives out energy and heats surroundings
During an exothermic reaction, are bonds formed or broken?
Formed
During an exothermic reaction, is energy released or taken in?
Released
Where does energy released from an exothermic reaction go?
It’s lost to the reaction’s surroundings and heats them up
Is enthalpy change positive/negative for exothermic reactions and why?
Negative - products end up with less energy than reactants
Define ‘endothermic’.
A reaction that takes in energy and cools the surroundings
During an endothermic reaction, are bonds formed or broken?
Broken
Is enthalpy change positive/negative for endothermic reactions and why?
Positive - products end up with more energy than reactants
Define ‘enthalpy change’.
Amount of energy transferred to and from surroundings
Why are standard conditions used when calculating enthalpy change?
They are set conditions which allows us to compare enthalpy changes
What temperature is used in standard conditions?
298K
What pressure is used in standard conditions?
1atm
What concentration is used in standard conditions?
1 moldm-3
How do you convert K to degrees C?
Minus 273
