So if we take a look here at this example question, it says which of the following represents a physical property. Now remember, a physical property deals with something we can observe with our senses, whereas a chemical property really talks about a compound and the chemical reaction it undergoes.
Now if we look at A, it says potassium metal is extremely reactive when placed in water. So we're talking about the reactivity of potassium within water. Reactivity is a chemical property. Next, rusting is a common issue with aluminum. We talk about rusting before. We say that rusting is how the surface of a metal interacts with oxygen in the air. It undergoes a chemical reaction. And since we're talking about rusting as a type of chemical reaction, this could represent a chemical property.
Neon has an unreactive nature, whether something is reactive or non reactive or unreactive, we're talking about its reactivity. So that is a chemical property. The butane in the lighter is highly flammable. Flammability is an example of a chemical property. The answer here has to be option E. Here it says mercury is a silvery liquid at 25°C. We're talking about its appearance, its color. Color is one of the first physical properties we discussed, so E would have to be my answer.
So just remember, when we talk about a physical property, it's something we can observe through the use of our senses. A chemical property has more in line to do with an object and how it undergoes a chemical reaction.