Chemistry Question

Question

Liquid sodium is being considered as an engine coolant. How many grams of liquid sodium (minimum) are needed to absorb 9.90 MJ of energy in the form of heat if the temperature of the sodium is not to increase by more than 10.0 °C? Use 𝐶P=30.8 J/(K⋅mol) for Na(l) at 500 K.

Answer 1

in order to solve this problem we will use the eqation

q=mCdT

q= energy in Joules. Given to us as 9.9MJ= 9.9E6J

m= mass or moles. In this case we will use moles of sodium because the specific heat capacity (Cp) is given un units of J/K mol. we will then convert moles to grams using the molar mass of sodium (22.9897 g/mol)

C= specific heat capacity. given to us as 30.8 J/(K mol)

dT= change in temperature. given to us as 10 degrees

9.9E6=m (30.8)(10)

m=3.214E4 moles

3.214E4 mol X (22.9897g/mol)= 7.39E5 g Na