1) Endothermic
2) Heat absorbed by reaction = 2511.6J
3)ΔH_rxn = 18.2 kJ/ mol
Explanation:
Mass of KCl = 10.3 g
Moles of KCl = mass of KCl / molar mass of KCl
= 10.3 g / 74.5513 g/mol
=0.138 mol
Mass of water, m = 200 g
Specific heat of water, C= 4.186 Jg^-1°C^-1
T_initial = 22.0C
T_final = 19.0°C
ΔT = T_final - T_initial
=19.0°C - 22.0°C
= -3.0°C
Heat absorbed = Heat released
q_rxn =-q_water
so,
q_water = m CΔT
substitute
q_water = 200g * 4.186J g^-1 °C^-1 *(-3.0°C)
= -2511.6J
Heat absorbed by reaction = 2511.6J
q_rxn = -q_water = 2511.6J
ΔH_rxn = q_rxn /moles of KCl
=2511.6J / 0.138 mol
ΔH_rxn =18.2kJ / mol
The reaction is a endothermic reaction.