Iron rusts according to the chemical equation 4Fe + 3O2 →

Question

2Fe2O3.

If a scientist weighs a shiny new iron nail, allows it to rust, and then weighs it again, what will she discover?

Responses

The rusty nail weighs more than when it was new.
The rusty nail weighs more than when it was new.

The rusty nail weighs less than when it was new.
The rusty nail weighs less than when it was new.

The mass of the nail did not change when it rusted.

Answer 1

In the rusting process of iron, the chemical equation shows that iron (Fe) reacts with oxygen (O2) from the air to form iron oxide (rust), represented by \( Fe_2O_3 \). This reaction involves the incorporation of oxygen into the iron, leading to the formation of a compound that has a higher mass than the original iron alone.

When the scientist weighs the shiny new iron nail and then measures it again after it has rusted, she will discover that:

The rusty nail weighs more than when it was new.

This is because the oxygen from the air has combined with the iron to create rust, adding mass to the nail.