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If you combine 300.0 mL of water at 25.00 ∘ C and 120.0 mL of water at 95.00 ∘ C, what is the final temperature of the mixture? Use 1.00 g/mL as the density of water.

Respuesta :

Answer : The final temperature of the mixture is [tex]45^oC[/tex]

Explanation :

In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.

[tex]q_1=-q_2[/tex]

[tex]m_1\times c\times (T_f-T_1)=-m_2\times c\times (T_f-T_2)[/tex]

And as we know that,

Mass = Density × Volume

Thus, the formula becomes,

[tex](\rho\times V_1)\times c\times (T_f-T_1)=-(\rho\times V_2)\times c\times (T_f-T_2)[/tex]

where,

c = specific heat of water = [tex]4.18J/g^oC[/tex]

[tex]\rho[/tex] = density of water = 1.00 g/mL

[tex]V_1[/tex] = volume of water at [tex]25.00^oC[/tex] = 300.0 mL

[tex]V_2[/tex] = volume of water at [tex]95.00^oC[/tex] = 120.0 mL

[tex]T_f[/tex] = final temperature of mixture = ?

[tex]T_1[/tex] = initial temperature of water = [tex]25.00^oC[/tex]

[tex]T_2[/tex] = initial temperature of water = [tex]95.00^oC[/tex]

Now put all the given values in the above formula, we get

[tex](1.00g/mL\times 300.0mL)\times (4.18J/g^oC)\times (T_f-25.00)^oC=-(1.0g/mL\times 120.0mL)\times 4.18J/g^oC\times (T_f-95.00)^oC[/tex]

[tex]T_f=45^oC[/tex]

Therefore, the final temperature of the mixture is [tex]45^oC[/tex]