Question

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part a

how much energy (in j) is lost when a sample of iron with a mass of 28.0 g cools from 78.0 °c to 26.0 °c?
express your answer with the appropriate units.

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Explanation:

Step1: Determine the formula

The formula for heat energy \(q = mc\Delta T\), where \(m\) is mass, \(c\) is specific heat capacity (for iron, \(c = 0.45\space J/g^{\circ}C\)), and \(\Delta T=T_{final}-T_{initial}\)

Step2: Calculate \(\Delta T\)

\(\Delta T=26.0 - 78.0=- 52.0^{\circ}C\)

Step3: Substitute values into the formula

\(m = 28.0\space g\), \(c = 0.45\space J/g^{\circ}C\), \(\Delta T=-52.0^{\circ}C\)
\(q=(28.0\space g)\times(0.45\space J/g^{\circ}C)\times(- 52.0^{\circ}C)\)

Step4: Perform the calculation

\(q=28\times0.45\times(-52)\)
\(q = 12.6\times(-52)\)
\(q=-655.2\space J\)

The negative sign indicates heat loss.

Answer:

\(655\space J\)