5. A sample of an unknown metal has a mass of 120.4 g. As the sample cools from 90.5°C to 25.7°C, it releases 7020. J of energy. What is the

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5. A sample of an unknown metal has a mass of 120.4 g. As the sample cools from 90.5°C to 25.7°C, it releases 7020. J of energy. What is the specific heat of the sample? Identify the metal among those in the data table below. Finally, is this endothermic or exothermic?

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Philomena 1 month 2021-08-15T05:23:17+00:00 1 Answers 3 views 0

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    2021-08-15T05:24:28+00:00

    Answer: The specific heat capacity of the sample is 0.899 J/g^{o}C and as heat is released in this reaction so it is exothermic in nature.

    Explanation:

    Given: Mass = 120.4 g

    Heat energy released = -7020 J

    Initial temperature = 90.5^{o}C

    Final temperature = 25.7^{o}C

     Formula used is as follows.

    q = m \times C \times (T_{2} - T_{1})

    where,

    q = heat energy

    m = mass of substance

    C = specific heat capacity

     T_{1} = initial temperature

     T_{2} = final temperature

    Substitute the values into above formula as follows.

    q = m \times C \times (T_{2} - T_{1})\\-7020 J = 120.4 g \times C \times (90.5 - 25.7)^{o}C\\C = \frac{-7020 J}{120.4 \times (-64.8^{o}C)}\\= \frac{7020 J}{7801.92} J/g^{o}C\\= 0.899 J/g^{o}C

    When heat is released in a process or reaction then it means it is exothermic in nature.

    Thus, we can conclude that the specific heat capacity of the sample is 0.899 J/g^{o}C and as heat is released in this reaction so it is exothermic in nature.

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