When 131.0 mL of water at 26.0°C is mixed with 81.0 mL of water at 85.0°C, what is the final temperature? (Assume that no heat is lost to the surroundings; d of water is 1.00 g/mL.)

Respuesta :

Answer:

63.52°C is the final temperature

Explanation:

1) 131.0 mL of water at 26.0°C

Mass of water = m

Volume of the water =131.0 mL

Density of the water = 1.00 g/mL

[tex]Density=1.00 g/mL=\frac{m}{131.0 mL}[/tex]

m = 131.0 g

Initial temperature of the water = [tex]T_i[/tex] = 26.0°C

Final temperature of the water = [tex]T_f[/tex]

Change in temperature ,[tex]\Delta T=T_f-T_i[/tex]

Heat absorbed 131.0 g of water = Q

[tex]Q=m\times c\times \Delta T[/tex]

2) 81.0 mL of water at 85.0°C

Mass of water = m'

Volume of the water =81.0 mL

Density of the water = 1.00 g/mL

[tex]Density=1.00 g/mL=\frac{m'}{81.0 mL}[/tex]

m' = 81.0 g

Initial temperature of the water = [tex]T_i'[/tex] = 85.0°C

Final temperature of the water = [tex]T_f'[/tex]

Change in temperature ,[tex]\Delta T'=T_f'-T_i'[/tex]

Heat lost by 81.0 g of water = Q'

[tex]Q'=m'\times c\times \Delta T'[/tex]

After mixing both liquids the final temperature will become equal fro both liquids.

[tex]T_f=T_f'[/tex]

Since, heat lost by the water at higher temperature will be equal to heat absorbed by the water at lower temperature.

Q=-Q' (Law of conservation of energy.)

Let the specific heat of water be c

[tex]m\times c\times \Delta T=m'\times c\times \Delta T'[/tex]

[tex]131.0 g\times c(T_f-26^oC)=-(81.0.0 g\times c(T_f-85^oC))[/tex]

[tex]T_f=63.52^oC[/tex]

63.52°C is the final temperature

According to conservation law, the amount of energy in a closed and isolated system remains constant and does not get reduced or added. The final temperature of the system is 63.52°C.

What are mass and temperature?

First, calculate the mass of the 131 mL of water:

Given,

  • Mass (m)= ?
  • Volume (V)= 131.0 mL
  • Density = 1.00 g/ml

[tex]\begin{aligned}\rm Mass &= \rm Volume \times \rm density\\\\\rm m &= 131.0 \;\rm g\end{aligned}[/tex]

Given,

Initial temperature [tex]\rm (T_{i})[/tex] =  26.0°C

The final temperature of the water = [tex]\rm (T_{f})[/tex]

Change in the temperature is calculated as,

[tex]\rm \Delta T = T_{f} - T_{i}[/tex]

Heat absorbed by 131.0 g of water = Q

The formula to calculate heat absorbed is,

[tex]\rm Q = m \times c \times \Delta T[/tex]

Second, calculate the mass of the 81 mL of water:

Given,

  • Mass (m') = ?
  • Volume (V')= 81.0 mL
  • Density = 1.00 g/ml

[tex]\begin{aligned}\rm Mass' &= \rm Volume \times \rm density\\\\\rm m' &= 81.0 \;\rm g\end{aligned}[/tex]

Given,

Initial temperature [tex]\rm (T'_{i})[/tex] = 26.0°C

The final temperature of the water = [tex]\rm (T'_{f})[/tex]

Change in the temperature is calculated as,

[tex]\rm \Delta T' = T'_{f} - T'_{i}[/tex]

Heat lost by 81.0 g of water = Q'

The formula to calculate heat lost is,

[tex]\rm Q' = m' \times c \times \Delta T'[/tex]

Both the liquids are mixed and the final temperature will be equivalent and given as, [tex]\Delta \rm T_{f} = \Delta T'_{f}[/tex]

According to the law of conservation,

Heat lost by the water (Q') = Heat absorbed by the water (-Q)

[tex]\begin{aligned}\rm m \times c \times \Delta T &= \rm m' \times c \times \Delta T'\\\\131 \times\rm c(T_{f} -26) &= -(81 \times\rm c(T_{f}- 85))\\\\\rm T_{f} &= 63.52 \circC\end{aligned}[/tex]

Therefore, 63.52°C is the final temperature.

Learn more about the law of conservation here:

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