Unit 18
Assignment A
Enthalpy inves.ga.on
Enthalpy change is when 1 mole of a substance reacts completely in oxygen when all reactants and
products are in their standard state. Enthalpy is used to determine if a reac=on was an endothermic
or exothermic reac=on, using enthalpy we are able to calculate the heat of reac=on of a chemical
process.
The equa=on for enthalpy change is as follows: H = U + PV
Enthalpy (H)
Internal energy (U)
Product of pressure (P)
Volume (V)
Entropy
Entropy is the distor=on of order in some amount of molecules, or the measure of randomness of
molecules in a system. An example of entropy is When a substance is heated, its energy rises (higher
enthalpy).
The molecules move quicker, which leads them to move in a less ordered manner, resul=ng in more
entropy than in their non-heated state.
To calculate the change in entropy, the equa=on is as follows:
Change in entropy = what you end up with – what you started with
The dissolving of anhydrous sodium carbonate in water
Equipment
- Polystyrene cup - S=rring rod
- 250 ml beaker
- Anhydrous sodium carbonate
- Dis=lled water
- Thermometer
- Weighing balance
- Clamp stand
- Measuring cylinder
Assignment A
Enthalpy inves.ga.on
Enthalpy change is when 1 mole of a substance reacts completely in oxygen when all reactants and
products are in their standard state. Enthalpy is used to determine if a reac=on was an endothermic
or exothermic reac=on, using enthalpy we are able to calculate the heat of reac=on of a chemical
process.
The equa=on for enthalpy change is as follows: H = U + PV
Enthalpy (H)
Internal energy (U)
Product of pressure (P)
Volume (V)
Entropy
Entropy is the distor=on of order in some amount of molecules, or the measure of randomness of
molecules in a system. An example of entropy is When a substance is heated, its energy rises (higher
enthalpy).
The molecules move quicker, which leads them to move in a less ordered manner, resul=ng in more
entropy than in their non-heated state.
To calculate the change in entropy, the equa=on is as follows:
Change in entropy = what you end up with – what you started with
The dissolving of anhydrous sodium carbonate in water
Equipment
- Polystyrene cup - S=rring rod
- 250 ml beaker
- Anhydrous sodium carbonate
- Dis=lled water
- Thermometer
- Weighing balance
- Clamp stand
- Measuring cylinder
