Practice It

Use the worked example above to help you solve this problem. A $109$ g block of an unknown substance with a temperature of $90\mathrm{.}0C$ is placed in a Styrofoam cup containing $0\mathrm{.}311$ kg of water at $20\mathrm{.}0C.$ The system reaches an equilibrium temperature of $22\mathrm{.}4C.$ What is the specific heat, $c_{x^{\text{'}}},$ of the unknown substance if the heat capacity of the cup is neglected?

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$\frac{J}{k}g*C$

Exercise

A $248$ g block of gold at $76\mathrm{.}0C$ is immersed in $155$ g of water at $25\mathrm{.}0.$ Find the equilibrium temperature, assuming the system is isolated and the heat capacity of the cup can be neglected.

${?}^{\text{'}}C$