A lead mass is heated and placed in a foam cup calorimeter containing 40.0 mL of water at 17.0°C. The water reaches a temperature of 20.0°C. How many joules of heat were re-leased by the lead?

Respuesta :

Answer: 502 Joules

Explanation:

To calculate the mass of water, we use the equation:

[tex]\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}[/tex]

Density of water = 1 g/mL

Volume of water = 40.0 mL

Putting values in above equation, we get:

[tex]1g/mL=\frac{\text{Mass of water}}{40.0mL}\\\\\text{Mass of water}=(1g/mL\times 40.0mL)=40.0g[/tex]

When metal is dipped in water, the amount of heat released by lead will be equal to the amount of heat absorbed by water.

[tex]Heat_{\text{absorbed}}=Heat_{\text{released}}[/tex]

The equation used to calculate heat released or absorbed follows:

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

q = heat absorbed by water

[tex]m[/tex] = mass of water = 40.0 g

[tex]T_{final}[/tex] = final temperature of water = 20.0°C

[tex]T_{initial[/tex] = initial temperature of water = 17.0°C

[tex]c[/tex] = specific heat of water= 4.186 J/g°C

Putting values in equation 1, we get:

[tex]q=40.0\times 4.186\times (20.0-17.0)][/tex]

[tex]q=502J[/tex]

Hence, the joules of heat were re-leased by the lead is 502