[purplemonkey123]

Hellooo!

I'm doing an lab with my online class (http://ksykang.tripod.com/chem/CHEM_HES.HTM)
I'm having trouble calculating the enthalpy of the neutralizaiton of solid sodium hydroxide

NaOH(s) + HCl(aq) H2O(l) + NaCl(aq)
my data
volume of hcl = 25ml of 2M
mass of naoh = 2g of 2M
temperature change: 30C
heat capacity = 4.184

I calculated qcal = 4326.67J
which would be qrxn = -4326.67J

I know i have to find dH by dividing q by moles but do i divide it by the moles of HCl or NaOH?

I'm assuming it'd be NaOH because for the other reaction in my lab (NaOH(s) --> NaOH (aq))
I found q then divided it by the moles of NaOH instead of water
... but im not even sure if that part is right...

[Vidya]

Check the limiting reactant ...divide it by moles of the limiting reactant or mole of water formed