Question

Using Table 9.4, calculate an approximate enthalpy (in kJ) for the reaction of 7.08 g gaseous methanol (CH3OH) in excess molecular oxygen to form gaseous carbon dioxide and gaseous water. (Hint, remember to first write the balanced equation.)

Answer 1

1.- 2CH3OH(g)+ 3O2(g) -> 2CO2(g) + 4H2O(g)

2.- you have to look in the table the delta H of formation for H2O(g), CO2(g), CH3OH(g), and O2(g)

3.- Then you have to multiply the values of each delta H for the correspondent coefficient from the balanced reaction (ej 4 x delta H water)

4.- Add delta H of the products and subtract the delta H of the reactants

Answer 2

Finally calculate how many moles of CH3OH you have in 7.08g and multiply the value calculated in step 4 by the moles in 7.08g and divide by 2