Question

completing sentences
choose the correct word or term for each statement. write your choice in the spaces provided

1. this rock in figure a is

usting\
a. rust forms when __ (limestone/iron) links up with __ (oxygen/carbon dioxide).

Explanation:

Rust is an iron oxide. The chemical formula for rust is \(Fe_2O_3\cdot xH_2O\). It forms when iron (\(Fe\)) reacts with oxygen (\(O_2\)) in the presence of water. Limestone is mainly \(CaCO_3\) and does not form rust. Carbon dioxide (\(CO_2\)) does not react with iron to form rust in the way oxygen does.

Answer:

a. iron; oxygen