[giayojoseph]

When 4.25 g of sodium hydroxide (NaOH) was dissolved in 150.00 g of water a value of 11.50 Celcius was obtained for ΔT.

Calculate the number of calories that would be produced if one mole of sodium hydroxide was dissolved. (ΔHsolnNaOH)


I think you use  Q = specific heat x mass x temperature change
but I keep getting wrong answer for some reason

Any help please ?

[gregdwulet]

I haven't checked the math on the first two questions, but I'm going to assume that they're correct since you seem to know what you're doing up to this point.

I'm not sure about the method that you were taught, but this is how I would do it:

1. Find the number of moles in 4.95g of NaOH (0.124 mol)
2. Once you have that, set up a simple proportion; .124mol NaOH released 1690 calories of energy by dissolving, therefore 1 mol of NaOH would release a proportionate amount of energy.

To my knowledge, the relationship of moles dissolved : energy released is linear...

Hope this helps,
Greg