1:Enthalpy Flashcards
What is the most exploited exothermic reaction?.
The oxidation of fuels by combustion.
What do you know when you see the units KJ mol^-1?
You know the enthalpy change refers to molar quantities in the equation.
How is change in enthalpy calculated?
Change in H = H of products - H of reactants.
Define exothermic
Exothermic refers to a reaction in which the enthalpy of the products is smaller than the enthalpy of the reactants resulting in heat loss to the surroundings.
Define endothermic
Endothermic refers to a reaction in which the enthalpy of the products is greater than the enthalpy of the reactants, resulting in heat being taken in from the surroundings.
What does the following mean? :
CH4 + 2O2 —–> CO2 + 2H20
Change in H = -890KJ mol.
So, 1 mol of CH4 reacts with 2 mol of O2 to form 1 mol CO2 and 2 mol H2O with a release of 890KJ of energy.
Why is respiration an important exothermic reaction for life?
Without it there would be no life.
Write the reaction for respiration.
C6H12O6 + 6O2 ——> 6CO2 + 6H2O
change in H = -2801 KJ miol^-1
Is the thermal decomposition of lime stone endothermic or exothermic?
The decomposition of calcium carbonate by heat is an important endothermic reaction used to make calcium oxide, CaO.
What are the uses of lime?
Lime has many uses, such as in the manufacture of cement and for treatment of acid soils in farmers.
What is the most important endothermic reaction for life?
Photosynthesis
What is the reaction for photosynthesis?
6CO2 + H2O —-> C6H12O6 + 6O2
