Question

calculate the amount of heat liberated (in kj) from 366 g of mercury when it cools from 77.0°c to 12.0°c. cₛ(of hg) = 0.139 j/(g°c)
-3301 kj
-3.31 kj
-4.53 kj

Explanation:

Step1: Identify the formula

$q = m\times C_s\times\Delta T$

Step2: Calculate the temperature change

$\Delta T=T_{final}-T_{initial}=12.0^{\circ}C - 77.0^{\circ}C=- 65.0^{\circ}C$

Step3: Substitute values into the formula

$q = 366\ g\times0.139\ J/(g^{\circ}C)\times(-65.0^{\circ}C)$
$q=366\times0.139\times(- 65.0)\ J$
$q=-3301.35\ J$

Step4: Convert to kJ

$q=\frac{-3301.35\ J}{1000}=-3.30135\ kJ\approx - 3.30\ kJ$

Answer:

-3.31 kJ