Can a Calorimeter Measure Fast Chemical Reactions?

In summary, the conversation discusses the introduction of Thermochemistry in a book, which includes the concept of heat and how a calorimeter works. It then delves into the creation of Hess Law and mentions that one of the reasons for its development is due to the inability of a calorimeter to calculate fast chemical reactions. However, the conversation raises the question of why a calorimeter cannot calculate these reactions and whether the water in the calorimeter will heat up or cool down over time. The conversation also explores the possibility of determining the heat of a single step in a quick multistep reaction and whether a calorimeter can be used to calculate the enthalpy variation of a fast single step reaction, or if Hess Law is needed for this calculation
  • #1
Sonim
4
0
TL;DR Summary
Question about enthalpy and fast reactions.
My book introduces Thermochemistry with the concept of heat and how a calorimeter works. After that, it explains the story behind Hess Law and says that one of the reasons it was created is because a calorimeter can't calculate fast chemical reactions, but it doesn't really say the problem with it. Why can't it calculate fast chemical reactions? Won't the water in the calorimeter heat up or cool down after some time?
 
Chemistry news on Phys.org
  • #2
How are you going to determine a heat of a single step of a quick multistep reaction?
 
  • #3
Supposing a fast single step reaction, is it possible to calculate its enthalpy variation using a calorimeter or I would need Hess Law to calculate it using other reactions?
 

1. What is Hess' Law?

Hess' Law is a principle in chemistry that states the total enthalpy change for a chemical reaction is independent of the pathway between the initial and final states. In other words, the overall energy change of a reaction is the same regardless of how the reaction takes place.

2. Who is Hess and how did he come up with this law?

Hess' Law is named after Germain Hess, a Swiss-Russian chemist who first proposed the principle in 1840. He based his theory on observations of heat changes in chemical reactions and the law of conservation of energy.

3. How does Hess' Law relate to thermodynamics?

Hess' Law is closely related to the first and second laws of thermodynamics. It is based on the principle of energy conservation, which states that energy cannot be created or destroyed, only transferred or converted. Hess' Law is also related to the concept of entropy, which is a measure of the disorder or randomness in a system.

4. What are the practical applications of Hess' Law?

Hess' Law is commonly used in chemistry to calculate the enthalpy change of a reaction that cannot be directly measured. It is also useful in predicting the energy changes of reactions and designing chemical processes, such as in the production of fuels and pharmaceuticals.

5. Are there any limitations to Hess' Law?

While Hess' Law is a useful tool in chemical calculations, it does have some limitations. It assumes that the reactants and products are in the same physical state and that the reaction takes place under standard conditions. It also does not account for the effects of temperature and pressure on the energy change of a reaction.

Similar threads

Replies
3
Views
1K
Replies
16
Views
2K
Replies
12
Views
1K
Replies
7
Views
931
  • Chemistry
Replies
2
Views
3K
Replies
14
Views
979
  • Biology and Chemistry Homework Help
Replies
11
Views
3K
Replies
36
Views
5K
Replies
2
Views
3K
Replies
33
Views
3K
Back
Top