In this video, we're going to talk about the difference between physical properties and chemical properties. When you think of properties, properties are characteristics. A physical property describes characteristics that does not change the chemical identity of the substance.
Whereas a chemical property, it describes a characteristic that will change the chemical identity of a substance. So, for example, boiling point. The boiling point of a substance is a physical property. When water boils, when it converts from a liquid to a gas, when it goes from water into steam, it's still water. The chemical identity is still H2O.
So if the chemical identity hasn't changed, you have a physical change. And boiling point is a characteristic of water. It's the temperature at which water boils.
And so, because the boiling process is associated with a physical change, boiling point, which is a characteristic of water, must be a physical property of water. So physical properties, physical changes, they're associated with each other. A property is simply a characteristic of a substance. So boiling point, melting point, freezing point, these are all physical properties.
Let's think of ice. When ice melts into liquid water, the chemical identity does not change. Ice is still H2O.
So any type of property where the state of matter is changing, that's a physical property. So melting point, boiling point, vaporization, that's another physical property. Now what about flammability?
When you hear the word flammability, is that a physical property or is that a chemical property? Flammability has to do with a substance burning. If you burn paper, you are changing the chemical properties of paper.
When you burn paper, The paper breaks down into carbon dioxide and water and maybe some other stuff as well. So the chemical identity is changing. You now have a new substance.
So therefore, flammability is a chemical property because it has to do with a change in substance, producing a new chemical substance. Now what about ductility? Is that a physical property or a chemical property?
When something is ductile, you need to know what that means. Copper is ductile. Copper can be pulled into a wire.
So if you have a copper bar metal... you can turn it into a wire. However, both substances are still copper. The substance did not change.
The chemical identity is still the same. So therefore, ductility, which has to do with turning a metal into metal wires, is a physical property. It's not a chemical property because it doesn't change the chemical identity of a substance, or it doesn't describe something that changes the chemical identity of a substance.
Okay, what just happened here? Now what about the word corrosive? If something is corrosive, what does that mean?
Are we describing a physical property or a chemical property? So if I say acid is corrosive, would you define it as a physical or chemical property? Corrosion has to do with a chemical reaction. Acid is corrosive because it can strip off electrons from metals. And whenever there's a chemical reaction, the characteristic that describes it is a chemical property.
So something that is corrosive, that's a chemical property of that substance. Something that is combustible... is also a chemical property of a substance.
For example, gasoline is combustible. That's a chemical property of gasoline. If you put gasoline in air and you add a spark to it to get things started, it's going to combust, it's going to react with oxygen, creating a large fire. So combustibility, or if something is combustible, that is describing the chemical property of that substance. Now what about malleability?
if something is malleable is that a physical property or chemical property Now let me tell you what it means when something is malleable. Let's say if you have a chunk of aluminum. You can hammer it into sheets and get aluminum foil or just a flat sheet.
So aluminum is malleable. Now, regardless if you have a large chunk of aluminum metal or if you have a flat sheet, it's still... aluminum the chemical identity is the same so if you take a chunk of aluminum and turn it into a flat sheet you haven't changed a chemical identity of the substance so this is associated for physical change so malleability is the physical property Now what about the word explosive?
If a substance is explosive, are we describing the substance's physical property or its chemical property? Something that is explosive tends to be combustible. So this is another chemical property.
It has to do with a reaction. TNT is explosive. Sometimes it could just react with itself.
It doesn't have to react with other things. Once you get it started, a chemical reaction will take place. So whether something is explosive or combustible, it has to do with a chemical reaction. So those are chemical properties.
Now what about color? Let's say the color of that book is red. Or those sheets are blue. These are physical properties. The color itself has nothing to do with a chemical reaction.
However... If you see a solution change in color, that is a chemical reaction. It indicates a reaction is taking place. But color itself is a physical property. But if you see a color changing, then a chemical reaction is taking place, which leads to a chemical change.
Now what about viscosity? Is viscosity a physical property or a chemical property? So for example, water is not viscous.
Water can flow easily. But something like syrup or honey, it's very viscous. viscosity has to do with the resistance of a fluid to flow so syrup and honey doesn't flow fast as water so the viscous viscosity is a physical property it describes how a fluid travels it doesn't really describe how a fluid reacts with something.
So whenever a word or property describes how something reacts, that's a chemical property. If it doesn't describe a reaction, it's going to be a physical property. Now what about pH?
Is the pH of a solution, is that a physical property or a chemical property? pH is a chemical property. Acids tend to react with most metals and the pH of an acid has to do with the strength of an acid.
A strong acid usually has a low pH number. And so by adjusting the pH, you can affect how an acid reacts with something. And so pH is a chemical property because it's associated with a reaction.
Density is a physical property. It describes how the atoms in matter, how close apart or how far apart. apart either. Something that has a high density has a lot of matter in a very small space.
Something that is not very dense, like a balloon, has a lot of space but not much matter. So density is a physical property. It doesn't describe how a substance reacts, but rather it describes, it relates mass with volume. It describes the distribution of matter within a certain space.
So other things that are physical properties, mass is a physical property, weight, these have to do with the quantity of matter or the force that they exert on the earth. It doesn't have to do with how they react with another element. A volume, that's another physical property.
Now what about taste? Taste is a chemical property. Let's say if lemonade tastes sour, it's because it's acidic.
Or that substance tastes bitter, it's basic. And so your body is reacting to the different pH levels in these solutions. So taste is a chemical property. The taste of lemonade is acidic, so that's describing the acidity of that drink.
So hopefully this video helps you to clarify the difference between physical properties and chemical properties. And that's all I got. Thanks for watching.