Getting tan under the sun

Bone-strengthening physical activity done increases bone-mineral content and bone density in youth.

Achemistry student needs of 40ml diethylamine for an experiment. by consulting the crc handbook of chemistry and physics, the student discovers that the density of diethylamine is 0.7 . calculate the mass of diethylamine the student should weigh out. round your answer to significant digits.

What is the equation for electrical work?