Chemical vs Physical changes

Course:
Chemistry

How do you know if CHEMISTRY is happening? What changes let you know a Chemical Reaction has happened, vs just a Physical change? For instance, you can probably tell ice melting is a physical change - especially because you can reverse it by sticking the water into a freezer and making ice cubes. Water is still H2O, whether it’s frozen, or liquid, or even gas. But what about something more complicated, like butter? When you melt butter on the stove, at first you just get melted butter. But what about when it browns? Do you know that browning is a special kind of chemical reaction - the MAILLARD reaction? There are other kinds of browning, too, like the DECOMPOSITON reaction that takes place when you melt sugar to make caramel. In this video, we’ll talk about what distinguishes a chemical change from a physical change, & what are some signs to look for so you can tell the difference. To do this, first you’ll need to be able to recognize what is a physical property, vs what is a chemical property of matter. Can you name some physical properties of matter? What about some chemical properties? Here’s a hint - you won’t really observe a chemical property of matter until it is actually taking part in a reaction!

How do you know if a chemical reaction is taking place? Can you tell the difference between a chemical change and a physical change? For instance, you can probably tell ice melting is a physical change - especially because you can reverse it by sticking the water into a freezer and making ice cubes. Water is still H2O, whether it’s frozen, or liquid, or even gas. But what about something more complicated, like butter? When you melt butter on the stove, at first you just get melted butter. But what about when it browns?

Do you know that browning is a special kind of chemical reaction - the MAILLARD reaction?

There are other kinds of browning, too, like the DECOMPOSITON reaction that takes place when you melt sugar to make caramel. In this video, we’ll talk about what distinguishes a chemical change from a physical change, & what are some signs to look for so you can tell the difference. To do this, first you’ll need to be able to recognize what is a physical property, vs what is a chemical property of matter. Can you name some physical properties of matter? What about some chemical properties? Here’s a hint - you won’t really observe a chemical property of matter until it is actually taking part in a reaction!

Video: Chemical vs Physical Changes

Handout: Video Notes Worksheet

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