A volume of 105 mL of H₂O is initially at room temperature (22.00°C). A chilled steel rod at 2.00°C is placed in the water. If the final temperature of the system is 21.40°C , what is the mass of the steel bar? Use the following values: specific heat of water = 4.18 J/(g⋅°C) specific heat of steel = 0.452 J/(g⋅°C) Express your answer to three significant figures and include the appropriate units.

Respuesta :

Answer:

30.0 grams is the mass of the steel bar.

Explanation:

Heat gained by steel bar will be equal to heat lost by the water

[tex]Q_1=-Q_2[/tex]

Mass of steel= [tex]m_1[/tex]

Specific heat capacity of steel = [tex]c_1=0.452 J/g^oC[/tex]

Initial temperature of the steel = [tex]T_1=2.00^oC[/tex]

Final temperature of the steel = [tex]T_2=T=21.40^oC[/tex]

[tex]Q_1=m_1c_1\times (T-T_1)[/tex]

Mass of water= [tex]m_2= 105 g[/tex]

Specific heat capacity of water= [tex]c_2=4.18 J/g^oC [/tex]

Initial temperature of the water = [tex]T_3=22.00^oC[/tex]

Final temperature of water = [tex]T_2=T=21.40^oC[/tex]

[tex]Q_2=m_2c_2\times (T-T_3)[/tex]

[tex]-Q_1=Q_2[/tex]

[tex](m_1c_1\times (T-T_1))=-(m_2c_2\times (T-T_3))[/tex]

On substituting all values:

[tex](m_1\times 0.452 J/g^oC\times (21.40^o-2.00^oC))=-(105 g\times 4.18 J/g^oC\times (21.40^o-22.00^o))[/tex]

we get, [tex]m_1 = 30.0314 g\approx 30.0 g[/tex]

30.0 grams is the mass of the steel bar.