Antoine Lavoisier

Can any one help with a few questions...

In 1789 Antoine Lavoisier did a series of reactions where he oxidised tin to tin-calx (SnO2). Lavoisier found that 1 kg of air always reacted with 0.78 kg of tin to yield 0.99 kg of tin-calx and leave 0.79 kg of gas inerts.

(a) Write a balanced equation for this reaction (including state symbols).

(b) Did Lavoisier measure things correctly? Does 1 kg of air react with 0.78 kg of tin yield 0.99 kg of tin calx? (Show your working to confirm your decision).

© Calculate the enthalpy change for the reaction of tin with oxygen.

Given the following information,

SnO2(s): ΔfHº = -580.7 kJ mol-1 and Sº = 52.3 J mol-1 K-1

Sn(s): Sº = 51.6 J mol-1 K-1

O2(g): Sº = 205.0 J mol-1 K-1

Is this reaction an exothermic or endothermic process?_______________________

(d) Calculate the entropy change for the reaction of tin with oxygen.

I really need some help, any suggestion shints would be appreciated

ta ;-)