Question #eb3dd

1 Answer
May 1, 2017

206.00 #kJ mol^(-1) #


The formula to calculate the heat change of a reaction is
ΔH = -mcΔT (where m is the mass of the fluid whose temperature changes which in this case is water, c is the specific heat capacity of water and ΔT is the change in temperature of water)

Heat change when 0.025 mol of Na is added
= #-100 * 4.18*(35.75-25.00) #
= #-5138.5 J#

Now this is heat change for 0.025 mole of Na.
Enthalpy change means you have to calculate the heat change for 1 mole.

So enthalpy change for 1 mole of Na is #-5138.5/0.025# = 205540 J= 206.00 #kJ mol^(-1) #