Question

A student makes several observations about a piece of iron. Which observation describes a chemical property of the iron?

A.
Its mass is 52 grams.
B.
Its density is 7.9 grams/centimeter3.
C.
It rusts when exposed to air.
D.
It conducts electricity.

Answer 1

The correct answer is option C.

Step-by-step explanation:

Chemical property is defined as the property of a substance which is observed during a reaction where the chemical composition identity of the substance gets changed.

For Example: reactivity , toxicity etc.

Physical property is defined as the property which can be measured and whose value describes the state of physical system. For Example: State, density etc.

The chemical property observed by the the student is that iron rusts when exposed to air. The oxygen present in the air reacts with iron to form reddish brown compound named rust.

`4Fe(s)+3O_2(g)\rightarrow 2Fe_2O_3(s)`

Here, iron's reactivity is observed which is a chemical property of the iron.

Where mass , density and being a electricity conductor are physical properties.

Answer 2

Answer:The correct answer is option C.

Step-by-step explanation:

Chemical property of the substance is a property which is observed in a chemical reaction during which identity or composition of the substance changes.

Iron when exposed to air ,react with atmospheric oxygen to from ferric oxide which is a reddish brown in color.Also termed as Rust.

`Fe(s)+O_2(g)\righhtarrow Fe_2O_3(s)(\text{Reddish brown})`

Hence, the correct answer is option C.