[DD_]

G'day, i have a few questions regarding the calculation of enthalpy of the following scenarios.

any help at all appreciated

1. the first one askes what enthalpy is if i add 0.25 grams of Mg powder to 100ml 1.0M HCl with a calibration factor of 359 and a tempreture change of 8.1 degrees

for this one i can just use 359*8.1 divide by number of moles of mg right?

2. the second one asks for enthalpy if i have 50ml HCl (at 20.1 degrees) and add it to 50ml NaOH (at 21.7 degrees) with same calibration factor and a tempreture change of 4 degrees

(this one i'm fairly sure but not certain that i have to find the limiting reactiant, but yeah, i'm a tad confused by this one)

3. the last one asks for enthalpy if i have 3 grams of KNO3 and add it to 100ml of water (at 19 degrees) with a tempreture decreasse of 1.7 degrees using same calibration factor as before

(not sure on this one, do i have to use the standard water thing of 4.19 or whatever?)

any help on all/either of these is a great help to me,
cheers

-DD