A student drops two metallic objects into a 120 g steel container holding 150 g of water at 25�C. One object i?

A student drops two metallic objects into a 120 g steel container holding 150 g of water at 25�C. One object is a 210 g cube of copper that is initially at 85�C, and the other is a chunk of aluminum that is initially at 5.0�C. To the surprise of the student, the water reaches a final temperature of 25�C, exactly where it started. What is the mass of the aluminum chunk? ______g