Internal energy, U, is equal to the work done or by the system, plus the heat of the system:
<span>ΔU=q+w </span>in the question they tell you the work done by the system, and the internal energy:
8185 J= -346 J + q work is negative because it was done BY the system.
substitute in: <span>q=m∗Cp∗ΔT</span> and solve for <span>Cp</span><span>. </span> ------------------------------------- remember that <span>ΔT=<span>Tf</span>−<span>Ti </span></span> so the equation, really, is: <span>q=m∗Cp∗(<span>Tf</span>−<span>Ti</span>)</span><span>
------------------------------------------ </span> <span>185J=−346J+[m∗Cp∗(<span>Tf</span>−<span>Ti</span>)]
</span>plug in the rest of your values and solve for <span><span>Cp</span></span>
