Why is it written "ha'Ohel"?
Radak based on Targum Yonasan: Chiram made for Shlomo in the Beis ha'Mikdash, Kelim like those in the Ohel Mo'ed.
What is the meaning of "Memurat"?
Radak: It is free from any rust or impurities. Malbim - it is very expensive. Only the first Chiram knew how to work with it; his son worked only with regular copper.