What is Scientific definition of a compound?

In 2002, the rare earth elements mine in mountain pass, california was closed because

A5 mole sample of liquid acetone is converted to a gas at 75.0°c. if 628 j are required to raise the temperature of the liquid to the boiling point, 15.600 kj are required to evaporate the liquid, and 712 j are required to raise the final temperature to 75.0°c, what is the total energy required for the conversion?

What element has similar physical and chemical properties as boron.