energy change in industry Flashcards
How do you convert from oc to K?
°C + 273.15 = K. Kelvin to Celsius: Add 273.
Define enthalpy
THe amount of energy used or released in a chemical reaction
standard conditions of enthalpy
298K 100 kPa
What is the symbol for standard conditions?
⦵
Give the units for enthalpy change
Jmol-1
What is meant by system?
The system is the chemicals that are reacting
What is meant by surroundings?
Everything else (the surroundings )
Define ΔHr in full
The energy change when reactants form products in the molar quantities given in the reaction under standard conditions
Define ΔHc in full
The enthalpy change that occurs when one mole of a substance is burnt completely in oxygen under standard conditions.
Define ΔHh in full
The energy released when one mole of gaseous ions is dissolved in water to make an infinitely dilute solution under standard conditions
When the reaction is exothermic, is the energy change positive or negative?
negative
When the reaction is endothermic, is the energy change positive or negative?
positive
Why does ΔHC for O2 = 0
because combustion means burning a substance completely in oxygen and if you burn oxygen in oxygen nothing will change
Why does ΔHfo for elements in their standard states = 0?
because they are already in their standard state so you cant form them from thier standard state
What is specific heat capacity
The specific heat capacity of a material is the energy required to raise one kilogram (kg) of the material by one degree Celsius (°C).
