so, I was doing this problem to study for tomorrow's test...

"When a 6.50-g sample of solid Sodium Hydroxide dissolves in 100.0g of water in a coffee cup calorimeter, the temperature rises from 21.6C to 37.8C. Calculate delta H in Kg/mol NaOH for the solution process

NaOH(s) ->Na+(aq) + OH-(aq)

Assume that the specific heat of the solution is the same as that of pure water"

This is what I did, I multipled 106.5g x 4.184J/gC x 16.2C to get the heat or delta H, which is 7.2187KJ. I then divided that by the number of moles of NaOH, which gives me the answer of 44.4KJ/mol NaOH...

However, the answer is -44.4KJ/mol NaOH... What in my calculations did do wrong? Delta T is positive because the final temperature is larger than the initial temperature, so I don't know what I did wrong...