14. Calculate the amount of heat liberated (in kJ) from 350 g mercury when it cools from 77.0 oC to 12oC. (The specific heat of mercury is 0.139 J/g oC)
q = mass x specific heat x (Tfinal-Tinitial)
To calculate the amount of heat liberated, we can use the formula:
Q = m * c * ΔT
Where:
Q = amount of heat liberated
m = mass of the substance (in grams)
c = specific heat capacity of the substance (in J/g oC)
ΔT = change in temperature (in oC)
Given:
m = 350 g
c = 0.139 J/g oC
ΔT = 77.0 oC - 12 oC
Let's plug in the given values into the formula and solve for Q.
Q = 350 g * 0.139 J/g oC * (77.0 oC - 12 oC)
Q = 350 g * 0.139 J/g oC * 65.0 oC
Q = 3153.5 J
To convert the result from joules (J) to kilojoules (kJ), divide by 1000:
Q = 3153.5 J / 1000
Q = 3.1535 kJ
Therefore, the amount of heat liberated from 350 g of mercury when it cools from 77.0 oC to 12 oC is approximately 3.1535 kJ.