Information:

Original temp of HCl: 23.3C
of NaOH: 23.8C
Final temp of the mixture: 36.7C

I am to find qH2O (assume 50 mL of solution and use average density of 1.02 g/mL) but I'm a bit lost.

I also need to find /\H and /\H per mole of H+a and OH- ions reacting, but I assumed I could not answer these 2 without qh20

heat=masswater*c*changetemp

= 50ml*1.02g/ml*cwater*(36.7-23.8)
look up c water, then after that, somehow you need to figure how many moles of HCl you had.

Is that 50 mL total? How much HCl and how much NaOH? What's the molarity of HCl and NaOH? You need to know mols H2O formed if you are to calculate dH/mol.

I see Bob Pursley ignored the difference in temperature. Is that 23.3 and 23.8 a typo?

So 50*1.02*4.18*12.9=2750J for qH2O?

25 mL of each solution. The molarity for each is 2 M.

Molarity is moles per liter, yes? So if I multiply the molarity, 2, by .025 L ... the moles of both will be .05? Or am I totally off?

To find qH2O, you can use the equation:

qH2O = mH2O * cH2O * ΔT

where:
- qH2O represents the heat absorbed or released by water (in joules)
- mH2O is the mass of water (in grams)
- cH2O is the specific heat capacity of water (4.18 J/g·°C)
- ΔT is the change in temperature (in °C)

Given that you have 50 mL of solution and the density of water is 1.02 g/mL, you can calculate the mass of water used:

mH2O = volume × density = 50 mL × 1.02 g/mL = 51 g

Now, we need to calculate the change in temperature (ΔT):

ΔT = final temperature - initial temperature = 36.7°C - ((23.3°C + 23.8°C) / 2) = 36.7°C - 23.55°C = 13.15°C

Substituting the values into the equation, we have:

qH2O = 51 g × 4.18 J/g·°C × 13.15°C = 3410.01 J

Therefore, qH2O is approximately 3410 J.

To calculate the ΔH (change in enthalpy) and ΔH per mole of H+ and OH- ions reacting, you would indeed need the value of qH2O. The enthalpy change can be calculated using the equation:

ΔH = q / n

where:
- ΔH is the change in enthalpy (in joules per mole)
- q is the heat transferred in the reaction (in joules)
- n is the number of moles of the substance being studied

In this case, n would be the number of moles of H+ or OH- ions reacting. However, to determine the number of moles of ions reacting, you would need the balanced chemical equation for the reaction.

If you have the balanced equation and know the stoichiometric ratios of the reactants and products, you can calculate the moles of H+ or OH- ions reacting and then find ΔH per mole of those ions.

Please provide the balanced chemical equation for the reaction, and I can help you further with the ΔH calculation.