## Chemistry and Chemical Reactivity (9th Edition)

a) From the data given: $-25.4\ kJ\div 0.850\ g\times24.305\ g/mol=-726.3\ kJ/mol$ b) From the definition of heat capacity: $25400\ J= (750\ g\times4.184\ J/g.K+820\ J/K)\times(T-18.6)\ K$ $25400=3958(T-18.6)$ $T=25.0^{\circ}C$