Question

Liquid sodium is being considered as an engine coolant. How many grams of liquid sodium (minimum) are needed to absorb of energy in the form of heat if the temperature of the sodium is not to increase?

Answer 1

Answer:

See explanation below

Explanation:

First, you are not providing any data to solve this, so I'm gonna use some that I used a few days ago in the same question. Then, you can go and replace the data you have with the procedure here

The concentration of liquid sodium will be 8.5 MJ of energy, and I will assume that the temperature will not be increased more than 15 °C.

The expression to calculate the amount of energy is:

Q = m * cp * dT

Where: m: moles needed

cp: specific heat of the substance. The cp of liquid sodium reported is 30.8 J/ K mole

Replacing all the data in the above formula, and solving for m we have:

m = Q / cp * dT

dT is the increase of temperature. so 15 ° C is the same change for 15 K.

We also need to know that 1 MJ is 1x10^6 J,

so replacing all data:

m = 8.5 * 1x10^6 J / 30.8 J/K mole * 15 m = 18,398.27 moles

The molar mass of sodium is 22.95 g/mol so the mass is:

mass = 18,398.27 * 22.95 = 422,240.26 g or simply 422 kg rounded.