You can put a known amount sodium into some sort of time release mechanism such as a pill made from soluble material. Then you can place the sodium into a calorimeter with a known mass of water and record the temperature change the water undergoes during the reaction. Then you can use the equation q(water)=m(water)c(water)ΔT to find the amount of heat absorbed by the water. since the amount of heat absorbed by the water is the amount of heat released from the sodium, q(sodium)=-q(water). Than you can use the equation q(sodium)=m(sodium)c(sodium)ΔT and solve for c(sodium)
I hope this helps and feel free to ask about anything that was unclear in the comments.
A square mile = 27,878,400 square feet
A square mile also = 640 acres.
31,580/.
2000 mL is the answer because when going from grams to milligrams you move your decimal place to the right 3 times. So therefore it is 2000 mL.