1.) the density of iron is 7.8 g/cm3 and that of aluminum is 2.7 g/cm3. using a balance, you find that a block of iron has the same mass as a block of aluminum. which block has the larger volume? question 15 options: you cannot tell from the information given. the volumes are the same. the iron block the aluminum block 2.) iron combines with oxygen and water from the air to form rust. if an iron nail were allowed to rust completely, you should find that the rust weighs question 20 options: less than the nail it came from the same as the nail it came from more than the nail it came from it is impossible to predict. 3.)what is the reason for your answer to the last question? question 21 options: rusting makes the nail lighter. rust contains iron and oxygen. the nail flakes away. the iron from the nail is destroyed. the flaky rust weighs less than iron.