All the reactions in a path are added together.
The enthalpy of reaction does not depend on the steps taken in the reaction.(Apex)
Hess's law states that if a reaction takes place in several steps then its standard reaction enthalpy is the sum of the standard enthalpies of the intermediate reactions into which the overall reaction may be divided at the same temperature.
The concept behind Hess's law is that the change in enthalpy in going from an initial state to a final state is pathway-independent since enthalpy is a state function. Therefore, if we have a reaction in a series of steps, the change in enthalpy as when the reaction takes place in one step.
This may sound a bit abstract at the moment, but I can clarify it with a simple example.
Say you want to find the delta H1 of a reaction:
1. N2 (g) + O2 (g) --> 2NO2 (g)
However, you know the change in enthalpy for two other reactions (which we shall label 2 and 3 just to avoid confusion) :
2. N2 (g) + O2 (g) --> 2NO (g) delta H2 = 180 kJ
3. 2NO (g) + O2 (g) --> 2NO2 (g) delta H3 = -112 kJ
When you add reactions 2 and 3 together you get:
N2 (g) + O2 (g) + 2NO (g) + O2 (g)--> 2NO (g) + 2NO2
The 2NO(g) on each side cancel out and you are left with:
N2 (g) + O2 (g) --> 2NO2 (g)
which is the equation for which you would want to find delta H!
Therefore, using Hess's law, we can simply add delta H2 = 180 kJ and delta H3 = -112 kJ together to find our delta H for the first reaction since the second reaction and the third reaction add together to give us the first reaction.
Therefore delta H=180+(-112)=68 kJ
False, a statement that can be tested is a hypothesis. In a hypothesis "if...then..." format, one is presenting a possible solution to a question. A law is a proven statement or idea.
The statement "Matter can neither be created nor destroyed but can be changed in form" is the substance of the law of conservation of matter.
Statement that summarizes a pattern found in Nature is called "Scientific law". It is a description of an observed phenomenon in nature.
Process generating the waste.
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Ethos
The preceding preceding statement was visible.
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the first statement in ModuleB
this is the statement of newton's third law.
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No following statements were included.
The part of a conditional statement following the word "then" is the consequent. It is the action or outcome that will occur if the condition specified in the statement is met.
law
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Find the converse of the following statement. If it's a dime, then it's a coin.
statement statement