Enthalpy of Neutralisation Flashcards
What is calorimetry?
Calorimetry is the process by which the energy change of a reaction is measured using water as a medium.
Is neutralisation exo or endo?
Exothermic
Is neutralisation exo or endo?
Exothermic
What is the assumption that is made often in neutralisation?
delta H reaction = -delta H water
- The chemical reaction releases energy, the water absorbs energy and vice versa.
What is the common mistake?
Total volume
50mL + 50mL = 100mL
What is one thing that will strengthen your responses in Trials?
Diagrams + flowcharts
What do thermometers measure?
Thermometers measure the average particle energy.
What do thermometers measure?
Thermometers measure the average particle energy.
How does temp relate to enthalpy?
Enthalpy is the total internal energy in a system. Combine temp with the amount of particles (mass) and how well they absorb energy (shc), you get total energy.
What does shc?
Specific Heat Capacity
What formula do you use to calculate the enthalpy of water/reaction?
delta H = mCat equation
What is another common yr 12 mistake?
Dropping sig fig
check out alan wong’s msg about sig fig
When doing an enthalpy of neutralisation, check if there is a limiting reagent.
True -
What does identical solns mean?
HSC Wording - same volume + same initial temp
Do not say neutral soln. It is a neutralisation
Very common yr 12 mistake
What is the structure to find the enthalpy of neutralization?
- Chemical equation (balanced)
- Mcat equation
- Find out how much energy is lost (formula 2)
- How many moles n=cV
- Final cal.
What is the important formula to remember?
delta H reaction = -delta H water (assumption)
How do you find the limiting reagent?
- Balanced chemical equation
- Number of moles of species
- Check which one has less moles, taking into account the molar ratio
What is the volume of the species added at pH =7?
sample:
n(HCl) = n(NaOH) = 0.056mol
C= n/v = 0.056/(1.4) = 0.040L
where 1.4 mol/L is the concentration of NaOH
What is the final pH of a solution after the entire mixture is poured in?
- Find the moles in excess & convert into concentration
- Make sure to divide it on top of the total volume of the mixture
- Calculate the POH/pH depending on its presence in the reaction
