Answer: The final temperature of the mixture will be [tex]2.5^0C[/tex]
Explanation:
[tex]heat_{absorbed}=heat_{released}[/tex]
As we know that,
[tex]Q=m\times c\times \Delta T=m\times c\times (T_{final}-T_{initial})[/tex]
[tex]m_1\times c_1\times (T_{final}-T_1)=-[m_2\times c_2\times (T_{final}-T_2)][/tex] .................(1)
where,
q = heat absorbed or released
[tex]m_1[/tex] = mass of first sample of ethanol = 100 ml
[tex]m_2[/tex] = mass of second sample of ethanol = 300 ml
[tex]T_{final}[/tex] = final temperature = ?
[tex]T_1[/tex] = temperature of first sample of ethanol = [tex]25^oC=298K[/tex]
[tex]T_2[/tex] = temperature of second sample of ethanol = [tex]-5^oC=268K[/tex]
[tex]c_1[/tex] = [tex]c_2[/tex] = specific heat of ethanol
Now put all the given values in equation (1), we get
[tex]-100\times (T_{final}-298)=[300\times (T_{final}-268)][/tex]
[tex]T_{final}=275.5K=2.5^0C[/tex]
Therefore, the final temperature of the mixture will be [tex]2.5^0C[/tex]