A 12.1g piece of aluminum at 81.7^oC is placed in a calorimeter containing water at 23.4^oC. If the final temperature of the system is 24.9^oC, what is the mass of the water? specific heat of Al = 0.900 J/g*^oC; specific heat of water = 4.184 J/g*^oC

(a)  

Calculate the standard enthalpy change for the reaction :

2Al_(s)+Fe₂O_3(s) --> 2Fe_(s) + Al₂O_3(s)

given that:

2Al_(s)+3/2O_2(g) --> Al₂O_3(s) ΔH^o_rxn=-1669.8kJ/mol

2Fe_(s)+3/2O_2(g) --> Fe₂O_3(s) ΔH^o_rxn=-822.2kJ/mol

(a)  

Calculate the enthalpy change for the reaction:

2C_(graphite)+3H_2(g)--> C₂H_6(g)

given that:

C_(graphite)+O_2(g) --> CO_2(g) ΔH^o_rxn= -393.5kJ/mol

H_2(g)+1/2O_2(g) --> H₂O_(l) ΔH^o_rxn= -285.8kJ/mol

2C₂H_6(g)+7O_2(g) --> 4CO_2(g)+6H₂O_(l) ΔH^o_rxn= -3119.6kJ/mol

(a)  

Given the following data:

H_2(g) --> 2H_(g) ΔH^o_rxn= 436.4kJ/mol

Br_2(g) --> 2Br_(g) ΔH^o_rxn= 192.5kJ/mol

H_2(g) + Br_2(g) --> 2HBr_(g) ΔH^o_rxn= -72.4kJ/mol

Calculate ΔH^o_{rxn for}

H_(g) + Br_(g) --> HBr_(g)

(a)