posted by Anonymous .
How much heat (in kilojoules) is evolved or absorbed in the reaction of 2.65 g of Na with H2O?
2Na+2H2O ---> 2NaOH + 2H2 Delta H= -368.4
Is that 368.4 J/mole of reactant or 368.4 J/reaction shown? It makes a difference? Also, you have no units on 368.4; I assume that is joules.
How many moles Na do you have?
2.65 g/atomic mass Na = moles Na.
If 368.4 J heat is released for the reaction as shown, then set up a proportion.