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CHEMISTRY, M4 EQ-Bank 4

The chemical equation for the combustion of butane is given below:

Given that the standard enthalpy of formation of is –393 kJ mol and is –241 kJ mol , calculate the standard enthalpy of formation of butane.   (3 marks)

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→ The enthalpy change for the combustion of 2 moles of butane is -5754 kJ.

 
 
 
 
   

 

→ The standard enthalpy of formation of butane is .

CHEMISTRY, M4 EQ-Bank 6 MC

The chemical equation for photosynthesis is given below:

Which of the following does Not effect the value of    for this reaction?

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→ The    of    is because oxygen is in its elemental form.

→ The standard enthalpy of formation of any element in its standard state is zero.

→ Hence it will have no effect on the    for photosynthesis.

 

CHEMISTRY, M4 EQ-Bank 1

The chemical equation for the combustion of butanol is given below

         

  1. Define what the term 'standard enthalpy of formation' means.   (1 mark)
  1. Use the table data to calculate the standard enthalpy of formation of butanol.   (3 marks)
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a.   Standard enthalpy of formation:

→ The change in enthalpy when one mole of a substance is formed from its constituent elements in their standard states under standard conditions (298 K temperature and 100 kPa).

→ The elements must be in their most stable form at these conditions.

b.    

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a.   Standard enthalpy of formation:

→ The change in enthalpy when one mole of a substance is formed from its constituent elements in their standard states under standard conditions (298 K temperature and 100 kPa).

→ The elements must be in their most stable form at these conditions.
 

b.    
 
 
   

 
→ The standard enthalpy of formation of an element is 0.

CHEMISTRY, M4 EQ-Bank 2

  1. Identify Hess' Law.   (2 marks)

  2. Given these heats of formation, :

  1. Calculate for the combustion of:

i.  1 mole of ethane () to produce carbon dioxide and water.   (2 marks)

ii. 1 mole of ethane () to produce carbon monoxide and water.   (2 marks)

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a.    Hess’s Law:

→ The total enthalpy change for a reaction is the same, regardless of the route by which the chemical reaction occurs, provided the initial and final conditions are the same.

b.i.   

b.ii.   

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a.    Hess’s Law:

→ The total enthalpy change for a reaction is the same, regardless of the route by which the chemical reaction occurs, provided the initial and final conditions are the same.
 

b.i.   Enthalpy change:

→ complete combustion of 1 mole of ethane () to produce carbon dioxide and water.


 

b.ii.  Enthalpy change:

→ incomplete combustion of 1 mole of ethane () to produce carbon monoxide and water.

CHEMISTRY, M4 EQ-Bank 36

The enthalpies of formation for a number of chemical reactions are as follows:

                 

               

                         

Calculate the enthalpy change for the fermentation of glucose (reaction below) using the enthalpies of formation above.

   (3 marks)

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