A 100. g iron rod is heated to an unknown initial temperature. While cooling down to a temperature of 25.0 degree C, the rod releases 600.2 J of energy. What was its initial temperature? (The specific heat of iron is 0.452 J/g degree C)

a) 38.3 J
b) 11.7 J
c) 27.7 J
d) 22.3 J

Respuesta :

Answer: a)  [tex]38.3^0C[/tex]

Explanation:

As we know that,  

[tex]q=m\times c\times \Delta T=m\times c\times (T_{final}-T_{initial})[/tex]

where,

q = heat released  = -600.2 J

[tex]m[/tex] = mass of iron rod =100 g  

[tex]T_{final}[/tex] = final temperature =[tex]25.^0C[/tex]

[tex]T_{initial}[/tex] = initial temperature = ?

[tex]c[/tex] = specific heat of iron = [tex]0.452J/g^0C[/tex]

Now put all the given values in equation, we get

[tex]-600.2J=100\times 0.452J/g^0C\times (25.0-T_{initial})^0C][/tex]

[tex]T_{initial}=38.3^0C[/tex]

Therefore, the initial temperature of iron rod was [tex]38.3^0C[/tex]

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