00:02
Hi there.
00:03
In this question, we are trying to decide if what is described as a chemical change or a physical change.
00:09
So let's define both of these.
00:11
A chemical change is any change in matter that produces a new substance that has a new formula and new properties, or a different chemical formula and different properties.
00:50
We have some indicators to help us decide if a chemical change might be taking place.
00:59
And those would include a color change.
01:04
Not always, but frequently a color change is indication that you have a chemical change taking place.
01:14
The formation of a precipitate, that's when you mix two clear solutions together, and it becomes cloudy because you formed little pieces of solid.
01:29
So those little pieces of solid are called precipitates.
01:36
A change in energy.
01:37
So either energy goes in or energy comes out or production of energy.
01:54
And the last one is formation of bubbles.
01:58
Now this doesn't mean boiling.
02:01
This means that the reaction itself is producing a gas.
02:06
So we're not heating it up.
02:07
It is just bubbling during the reaction.
02:14
Okay, so those are indications of a chemical change.
02:17
Let's talk about a physical change.
02:19
Physical change is any change in matter that does not produce a new substance.
02:25
It might look different because it's been changed physically, but it's still the same chemical substance.
02:35
So it does not produce a new chemical substance.
02:45
Still has the same formula.
02:47
So for example, any phase change, anything changing from a solid to a liquid to a gas, it's still the same substance...