If you have 1kg of iron and 1kg of steel which would be heavier?

Answer 1

1 kilogram of mass weighs 2.205 pounds on earth, 5.76 ounces on the moon,

and 13.39 ounces on Mars.

Edit:

Short answer: it depends on the type of steel.

kg or lb/oz are both units of mass, but the term "heavier" only applies to weight.

The more dense substance will weigh more, if both are measured at the same place on Earth (or on any other planet with a fluid atmosphere).

Of course, there are many different kinds of steel, all with different densities depending on the densities of the alloy substances added to iron in the manufacturing process, but in all instances will be very close to that of iron. For this reason, the weights on Earth will be very similar two.

N.B.: Even the Moon has a very low density atmosphere, consisting primarily of Argon, though it is often considered to be surrounded by a vacuum in comparison to the Earth's atmosphere.