The burning of 80.3 g of SiH4 at constant pressure gives off 3790 kJ of heat. Calculate △H for this reaction. SiH4(g) + 2O2(g) ⟶ SiO2(s) + 2H2O(l).
A) -1520 kJ/mol rxn.
B) - 47.2 kJ/mol rxn.
C) - 4340 kJ/mol rxn.
D) -2430 kJ/mol rxn.
E) + 4340 kJ/mol rxn.

Answer asap need by wednesday morning explain how a buffer works, using an ethanoic acid/sodium ethanoate system including how the system resists changes in ph upon addition of a small amount of base and upon addition of a small amount of acid respectively. include the following calculations in your i. calculate the ph of a solution made by mixing 25cm3 0.1m ch3cooh and 40cm3 0.1m ch3coo-na+. [ka = 1.74 x 10-5 m] ii. calculate the ph following the addition of a 10cm3 portion of 0.08 m naoh to 500cm3 of this buffer solution. iii. calculate the ph following the addition of a 10cm3 portion of 0.08 m hcl to 200cm3 of the original buffer solution.