If 55.0 ml of ethanol (density=0.789g/ml)) initially at 9.0 ∘c is mixed with 55.0 ml of water (density=1.0g/ml) initially at 28.6 ∘c in an insulated beaker, and assuming that no heat is lost, what is the final temperature of the mixture?

Final temperature = 22.21  °C

Explanation:

Heat gain by ethanol = Heat lost by water

Thus,  

Where, negative sign signifies heat loss

Or,  

For ethanol:

Density = 0.789 g/mL

Volume = 55.0 mL

Considering the expression for density as:

So,

So, Mass= Density*Volume = 0.789 g/mL * 55.0 mL = 43.395 g

Initial temperature = 9.0 °C

Specific heat of ethanol = 2.57 J/g°C

For water:

Density = 1.0 g/mL

Volume = 55.0 mL

Considering the expression for density as:

So,

So, Mass= Density*Volume = 1.0 g/mL * 55.0 mL = 55.0 g

Initial temperature = 28.6 °C

Specific heat of water = 0.450 J/g°C

So,  

Final temperature = 22.21  °C