1.2. How Far? Entropy
What is entropy?
The interaction of energy and matter governs our lives. We take for granted our ability to use chemicals in batteries to produce sound from MP3 Player. We get into a car and use petrol to travel in hours distance that would have taken our ancestors days. Energy and matter interact on other scales too –from the remnants of the explosion of star hundreds of light years in diameter, to the nucleus of an atom 10-9 mm in diameter. The way in which energy and matter behave affects the entire universe.
The importance of this interaction between energy and matter has not always been recognised. The understanding of this area of science grew out of the industrial. Revolution and the rise of the steam engine …show more content…
Tables gives the enthalpy change for three reactions
Na(s) + ½Cl2(g) NaCl -411.2
H2(g) + 1/2O2(g) H2O -242.0
CH4(g) + 2O2(g) CO2(g) + -1461,9 Al three of these reactions are exothermics with a considerable amount of energy being released. Just as a stone tends to run downhill, energy tends to run downhill. The low energy state of the products is more stable than the higher energy state of reactants – everything always likes to go towards the most stable, or lowest energy.
In the upword slope, thre reactant molecules are coming together and breaking apart. Separating atoms in the reactant molecules requires bonds to be broken so this part of the reaction absorbs energy
In the downward slope, the product molecules are forming and moving apart. Producing product molecules involved forming bonds, so this part of the reaction release energy.
Thre are some endothermic reaction that are spontaneous. For example :
Br2(l) + Cl2(g) 2BrCl(g) H0 = 29,3 kJmol-1
H2O(s) H2O(l) H0 = +6,01 kJmol-1
You wil notice that both of these values are small compared the value. They do not require much energy. If large amount of energy be supplied endorthermic reaction is not likely to be
What is entropy?
The interaction of energy and matter governs our lives. We take for granted our ability to use chemicals in batteries to produce sound from MP3 Player. We get into a car and use petrol to travel in hours distance that would have taken our ancestors days. Energy and matter interact on other scales too –from the remnants of the explosion of star hundreds of light years in diameter, to the nucleus of an atom 10-9 mm in diameter. The way in which energy and matter behave affects the entire universe.
The importance of this interaction between energy and matter has not always been recognised. The understanding of this area of science grew out of the industrial. Revolution and the rise of the steam engine …show more content…
Tables gives the enthalpy change for three reactions
Na(s) + ½Cl2(g) NaCl -411.2
H2(g) + 1/2O2(g) H2O -242.0
CH4(g) + 2O2(g) CO2(g) + -1461,9 Al three of these reactions are exothermics with a considerable amount of energy being released. Just as a stone tends to run downhill, energy tends to run downhill. The low energy state of the products is more stable than the higher energy state of reactants – everything always likes to go towards the most stable, or lowest energy.
In the upword slope, thre reactant molecules are coming together and breaking apart. Separating atoms in the reactant molecules requires bonds to be broken so this part of the reaction absorbs energy
In the downward slope, the product molecules are forming and moving apart. Producing product molecules involved forming bonds, so this part of the reaction release energy.
Thre are some endothermic reaction that are spontaneous. For example :
Br2(l) + Cl2(g) 2BrCl(g) H0 = 29,3 kJmol-1
H2O(s) H2O(l) H0 = +6,01 kJmol-1
You wil notice that both of these values are small compared the value. They do not require much energy. If large amount of energy be supplied endorthermic reaction is not likely to be