<u>Given:</u>
Mass of Ba = 1.50 g
Mass of H2O = 100.0 g
Initial temp T1 = 22 C
Final Temp T2 = 33.1 C
specific heat c = 4.18 J/g c
<u>To determine:</u>
The reaction enthalpy
<u>Explanation:</u>
The heat released during the reaction is:
q = - mc(T2-T1) = - (100+1.5) g *4.18 J/g C * (33.1-22) C = -4709.4 J
# moles of Ba = Mass of Ba/Atomic mass of Ba = 1.5 g/137 g.mol-1 = 0.0109 moles
ΔH = q/mole = - 4709.4 J/0.0109 moles = - 432 kJ/mol
Ans : The enthalpy change for the reaction is -432 kJ/mol
To find the number of atoms in the sample of copper, we need its atomic mass and the use of the Avogadro's number to find the equivalent units in terms of atoms.
68.7 g Cu ( 1 mol / 63.55 g ) ( 6.022 x 10^23 atoms / 1 mol ) = 6.51 x 10^23 atoms Cu
