Answer:
If iron, Fe, and oxygen, O2, are in contact at high enough temperatures (and with plenty of oxygen around), the grey or reddish compound that forms is called iron(III) oxide with the formula Fe2O3
Step-by-step explanation:
Iron rusts. We all know that. But the chemical reactions behind rust are surprisingly complicated! We will return to them at the end of the course when we discuss corrosion (see section 11.6 in the text). Here, we focus simply on the main compounds formed between iron and oxygen. That there is more than one may surprise you. That there are not an infinite number of them (and in fact, there almost is, as well shall see!) is an example of the law of definite proportion, an idea so central to chemistry it is almost taken for granted today.