Butane C4H10 (g),(Hf = –125.7), combusts in the presence of oxygen to form CO2 (g) (Delta. Hf = –393.5 kJ/mol), and H2O(g) (Delta. Hf = –241.82) in the reaction: 2 upper C subscript 4 upper H subscript 10 (g) plus 13 upper O subscript 2 (g) right arrow 8 upper C upper O subscript 2 plus 10 upper H subscript 2 upper O (g). What is the enthalpy of combustion, per mole, of butane? Use Delta H r x n equals the sum of delta H f of all the products minus the sum of delta H f of all the reactants.

The enthalpy of combustion, per mole, of butane is -2657.4 kJ

Explanation:

The balanced chemical reaction is,

The expression for enthalpy change is,

Putting the values we get :

2 moles of butane releases heat = 5314.8 kJ

1 mole of butane release heat =

Thus enthalpy of combustion per mole of butane is -2657.4 kJ

- aluminum and copper chloride.

- the chloride ion to separate the aluminum from the oxygen so that the aluminum can react with the copper ions (and the water molecules).

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e