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A 134.0 g sample of an unknown metal is heated to 91.0⁰C and then placed in 125 g (125 mL) of water at 25.0⁰C. The final temperature of the water is measured at 31.0⁰C. Calculate the specific heat capacity of the unknown metal.

Respuesta :

Answer:

The specific heat capacity of the metal is approximately 0.3903 J/(g·°C)

Explanation:

The mass of the sample of the unknown metal, [tex]m_m[/tex] = 134.0 g

The temperature to which the metal is raised, [tex]t_m[/tex] = 91.0°C

The mass of water into which the mass of metal is placed, [tex]m_w[/tex] = 125 g

The temperature of the water into which the metal is placed, [tex]t_w[/tex]= 25.0°C

The final temperature of the water, [tex]t_f[/tex] = 31.0°C

The specific heat capacity of water, [tex]c_w[/tex] = 4.184 J/(g·°C)

The specific heat capacity of the metal =  [tex]c_m[/tex]

Therefore, by the first laws of thermodynamics we have;

The heat transferred = Heat supplied by the metal = Heat gained by the water

The heat transferred, ΔQ, is given as follows;

ΔQ = [tex]m_w[/tex]×[tex]c_w[/tex]×([tex]t_f[/tex] - [tex]t_w[/tex]) = [tex]m_m[/tex]× [tex]c_m[/tex]×([tex]t_m[/tex] - [tex]t_f[/tex])

125 × 4.184 × (31 - 25) = 134 × [tex]c_m[/tex] × (91 - 31)

∴ [tex]c_m[/tex] = (125 × 4.184 × (31 - 25))/(134 × (91 - 31)) ≈ 0.3903 J/(g·°C)

The specific heat capacity of the metal =  [tex]c_m[/tex] ≈ 0.3903 J/(g·°C)

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