139k views
2 votes
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?

User Nchpmn
by
8.1k points

1 Answer

1 vote

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.

Step-by-step 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 * C * (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 * C * (T_(2) - T_(1))\\-7020 J = 120.4 g * C * (90.5 - 25.7)^(o)C\\C = (-7020 J)/(120.4 * (-64.8^(o)C))\\= (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.

User Yauhen Sampir
by
7.2k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.