Question

If a shiny iron nail with an initial mass of 23.2 g is weighed after being coated in a layer of rust, would you expect the mass to have increased, decreased, or remained the same? a) Increased b)Decreased c)Remained the same d) Not enough information provided

Answer 1

The mass of the iron nail would increase due to the chemical reaction with oxygen forming rust, which adds to the nail's original mass.

Step-by-step explanation:

If a shiny iron nail with an initial mass of 23.2 g is weighed after being coated in a layer of rust, the mass would be expected to have increased. This is because rust is iron oxide (Fe2O3 xH2O), formed by the reaction of iron (Fe) with oxygen (O2) in the presence of water (H2O).

During this chemical reaction, oxygen from the air combines with the iron to create the rust, thereby increasing the amount of matter on the nail and subsequently its mass.

For example, the reaction that takes place could be represented as: Fe + O2 → Fe2O3. The mass of oxygen has been added to the original mass of the nail, explaining the increase in mass.

In cases where protection is required, such as with galvanized nails, the nail is coated with zinc which is more reactive than iron and oxidizes preferentially, thus preventing rust formation on the nail.