Grade 9 Chemistry Lesson 1 - Matter and the Particle Theory

Summary

This Grade 9 chemistry lesson introduces matter and the particle theory. It explains that matter has mass and volume, with examples of solids, liquids, and gases. The video covers changes in states, including melting, freezing, evaporation, condensation, sublimation, and deposition. It introduces the particle theory, stating that all matter is made of particles that move, and their energy affects their state (solid, liquid, or gas). The video also explains how energy influences particle movement and state changes, such as evaporation occurring even below boiling point.

Takeaways

• 😀 Matter is anything that has both mass and volume.
• 📏 Mass refers to the amount of matter in an object and is measured in grams, kilograms, and milligrams.
• 🌍 Weight changes depending on gravity, but mass stays the same, even in space.
• 🧪 Volume is the amount of space an object occupies, measured in liters or milliliters.
• 🧊 The three states of matter are solid, liquid, and gas, and they can change states through melting, freezing, evaporation, and condensation.
• 🔥 Sublimation is when a solid turns directly into a gas, while deposition is when a gas turns directly into a solid.
• ⚛️ The particle theory explains that all matter is made up of tiny particles, which are always moving and have spaces between them.
• 🔬 Particles of a pure substance are the same, but different substances have different particles.
• 💥 Adding energy to particles increases their movement, which can cause substances to change states (e.g., from solid to liquid to gas).
• 💧 Evaporation can occur at lower temperatures because some particles at the surface of a liquid have enough energy to escape into the air.

Q & A

What is matter, according to the video?

Matter is anything that contains both mass and volume.

How is mass different from weight?

Mass is the amount of matter in an object, whereas weight is the force exerted on an object due to gravity. Mass remains constant regardless of location, but weight can change depending on gravity, such as on the Moon.

What are the three states of matter described in the video?

The three states of matter are solid (e.g., a rock), liquid (e.g., water), and gas (e.g., air or the gas inside a balloon).

What is the difference between melting and freezing?

Melting is the process where a solid turns into a liquid, while freezing is when a liquid turns into a solid. Both processes occur at the same temperature for a given substance, such as water at 0°C.

What is sublimation and deposition?

Sublimation is when a substance changes from a solid directly to a gas (e.g., dry ice). Deposition is when a substance changes from a gas directly to a solid (e.g., frost).

What is the particle theory of matter?

The particle theory explains the structure and behavior of matter, stating that all matter is made up of tiny particles, which have spaces between them, are always moving, and have attractive forces between them.

How does particle movement differ in solids, liquids, and gases?

In solids, particles vibrate in place. In liquids, particles move past each other, and in gases, particles move freely and randomly.

What causes evaporation, and why do puddles evaporate even when it's not 100°C?

Evaporation occurs when particles at the surface of a liquid gain enough energy to escape into the air as gas. Even at lower temperatures, some particles in a puddle can gain enough energy to evaporate, causing the puddle to disappear over time.

What are attractive forces between particles, and how do they vary?

Attractive forces are the forces that pull particles together. These forces are stronger when particles are closer, as in solids, and weaker when they are farther apart, as in gases.

How does the energy of particles relate to the state of matter?

As energy is added to particles, they move faster. In solids, particles vibrate with low energy, in liquids they move more freely with moderate energy, and in gases they move rapidly with high energy.

Outlines

00:00

🧪 Introduction to Matter and Particle Theory

The first paragraph introduces the concept of matter and the particle theory in a Grade 9 chemistry lesson. Matter is defined as anything with mass and volume, and the difference between mass and weight is clarified. It explains that while weight changes based on gravity, mass remains constant. The three states of matter—solid, liquid, and gas—are briefly introduced with examples such as a rock, water, and air. Key state changes like melting, freezing, evaporation, condensation, sublimation, and deposition are also discussed, with a focus on the melting and freezing points being the same for a substance like water.

05:01

🔥 Energy and the Movement of Particles in Different States

The second paragraph focuses on how energy affects the movement of particles and the transitions between different states of matter. It explains how adding energy to a solid causes particles to vibrate more, eventually leading to a liquid state as they move past each other. With further energy, particles break free and become gas. Evaporation is discussed in detail, explaining how it can occur even if the temperature isn't 100°C, due to the varying energy levels of individual particles. This explains why puddles can evaporate at lower temperatures. The lesson wraps up with a teaser for the next topic: mixtures and pure substances.

Keywords

💡Matter

Matter is defined as anything that has both mass and volume, making it a fundamental concept in chemistry. In the video, matter is described as the substance that makes up everything around us, from solids like rocks to liquids and gases. The lesson explores how matter exists in different states and transitions between them.

💡Mass

Mass refers to the amount of matter in an object, measured in units such as grams or kilograms. In the video, mass is distinguished from weight by emphasizing that mass remains constant regardless of gravity, while weight changes based on the strength of gravitational pull, such as on the moon or in space.

💡Volume

Volume is the amount of space that a substance or object occupies, measured in liters or milliliters. The video explains volume in relation to matter, illustrating how solids, liquids, and gases each take up space, albeit in different ways, such as water filling a container versus air filling a balloon.

💡States of Matter

The three primary states of matter—solid, liquid, and gas—are highlighted in the video. Solids have tightly packed particles, liquids have particles that can move around each other, and gases have particles that move freely. The video also discusses changes between these states, such as melting, freezing, and evaporation.

💡Melting

Melting occurs when a substance changes from a solid to a liquid, such as ice turning into water. The video explains that the melting point is the same as the freezing point, and it uses the example of water melting at 0 degrees Celsius to illustrate this concept.

💡Evaporation

Evaporation is the process by which a liquid turns into a gas. The video uses the example of water boiling on a stove, but it also explains how puddles evaporate even when the temperature is below 100 degrees Celsius. This is due to some particles having enough energy to escape into the air.

💡Condensation

Condensation is the process where a gas turns into a liquid, often seen when cold objects cause moisture in the air to form droplets. The video gives the example of condensation forming on a cold pot, explaining how gas particles lose energy and come together to form a liquid.

💡Sublimation

Sublimation is when a solid turns directly into a gas without passing through the liquid phase. The video explains this using dry ice (solid carbon dioxide) as an example, which sublimates into gas under normal atmospheric conditions.

💡Particle Theory

The particle theory describes the structure and behavior of matter, stating that all matter is made up of tiny particles that are always in motion and have spaces between them. The video explores how this theory helps explain the different states of matter and how particles behave as energy is added or removed.

💡Attractive Forces

Attractive forces refer to the forces that pull particles of matter towards each other. The video discusses how these forces are stronger when particles are closer together, such as in solids, and how they weaken as particles move apart, like in liquids and gases.

Highlights

Matter is anything that contains both mass and volume.

Mass is how much matter is in an object, measured in grams, kilograms, and milligrams.

Mass should not be confused with weight; weight changes based on gravity, but mass remains constant.

Volume is the amount of space something takes up, measured in liters and milliliters.

The three states of matter are solid, liquid, and gas.

Melting occurs when a solid turns into a liquid, such as ice melting into water.

Freezing is when a liquid becomes a solid, like water freezing into ice. The freezing and melting points are the same, for example, 0°C for water.

Evaporation is the process of a liquid turning into a gas, like water evaporating when boiled.

Condensation happens when a gas turns into a liquid, such as moisture forming on a cold surface.

Sublimation is when a solid turns directly into a gas, like dry ice (solid CO2) transforming into gas.

Deposition is the reverse, where a gas changes directly into a solid, an example being frost formation.

The particle theory describes the structure and behavior of matter, stating that all matter is made of tiny particles.

Particles of a pure substance are identical, but different substances consist of different particles.

Particles are always in motion; the more energy they have, the faster they move, and the type of movement depends on the state of matter.

When particles gain energy, they move more, weakening their bonds, transitioning from solid to liquid and then to gas as energy increases.

Transcripts

hi there welcome to Mr lehan teaches you

stuff this is grade nine chemistry

lesson one matter and the particle

theory so first thing we want to look at

is what is matter and matter is anything

that contains both mass and volume so we

might as well Define those as

well mass is how much matter is in an

object we measure mass in grams

kilograms milligrams stuff like

that um it's very important that we

don't get Mass confused used with weight

um so you may weigh 100 pound and when

you go into space let's say you don't

weigh 100 pounds you're floating around

weightless uh but you're not floating

around massless you still are made up of

the same amount of

matter um similarly if you step on a

scale on the

moon uh it'll say that you weigh less

right because you're not pushing down as

hard on that scale because gravity is

not as hard or not as strong but you

will not have less Mass you'll have the

same amount of mass volume is how much

space something takes up uh we measure

volume in liters and milliliters

Etc so the three states of matter are

solid like this rock liquid like a glass

of water and gas like the gas inside

this balloon or possibly the gas in the

air that that balloon is floating

through

uh there are several changes in state so

melting is when something goes from a

solid to a

liquid so there's an example some ice

cubes

melting freezing is when a liquid turns

into a solid uh like this water that I

left in the

freezer um and it's important to note

that the melting point is the same as

the freezing point so for water for

example that's 0 degrees Celsius so uh

the same temperature at which something

melts is the same one which it will

start to

freeze uh evaporation is when something

goes from a liquid to a gas so when

you've got water boiling on the stove

some of that water will

evaporate uh condensation it's when

something goes from a gas to a liquid if

you ever get uh a cold pot for example

out of the fridge uh you might notice

that there's condensation around

it uh now for two that you may not have

heard of subl and deposition sublimation

is when something goes from a solid to a

gas um so an example of that would be

dry ice uh which is basically solid

carbon dioxide it changes directly into

a

gas uh deposition gas to a solid this is

more common uh than you might think um

that's what Frost is so if you ever see

frost on a pine Branch like this or

frost on a

window uh that is solid water uh that

has just come out of the air it went

directly from gaseous water to solid

water now how does this all relate to

the particle uh the particle theory was

created to describe the structure and

behavior of

matter and there's five main points to

the particle theory so we'll take a look

at

those first point is that all matter is

made up of tiny

particles and all of those particles

have spes in between them so there's a

little bit of room between each one of

those

particles Point number three all

particles of one pure substance are the

same different substances are made of

different particles so if we've got two

substances here uh they're both pure

substances they're all made of the same

type of

particle um but since they're different

types of substances they have different

types of particles making them up one in

this case is green and one is

blue uh number four the particles are

always moving the more energy the

particles have the faster they

move so even for a solid object so the

computer you're watching on this on your

hand uh your desk all the particles that

make up that desk or hand or computer

are moving a little bit um to the extent

or the extent to which they move around

uh determines whether a solid a liquid

or a gas um but they're all moving a

little

bit and there are attractive forces

forces between the particles these

forces are stronger when the particles

are closer together so the three

particles here they're fairly close

together they're very attracted to each

other whereas this one off by itself at

the bottom is not as attracted to the

other

ones so how does the particle theory

relate to the states of matter um as

energy is added to particles they move

around more this causes the bonds

between the particles to weaken so here

we have some very low energy particles

this is a

solid um now if this solid is at

Absolute Zero um then it's not going to

be moving around at all but as we add a

little bit of energy to it a little bit

of

heat um those particles will start to

jiggle around more so it's still a solid

no one none of the particles have are

moving past each other but they'll

they'll kind of Shake in

place now when you add even more energy

the particles get so much energy that

they move move past each other so if

they can slide past each other and move

around that substance is now a

liquid then as you add even more energy

uh the particles are no longer bonded to

each other so they're flying around

randomly uh the substance is now a gas

these are very high energy particles you

can tell by the looks on their

faces um now evaporation is when

something turns from a liquid to a gas

and that happens at 100 degrees

C but you may think well why is it that

puddles disappear puddles evaporate but

it's not 100 degrees out um and the

reason why is because when those

particles are just randomly moving

around in a

puddle um some of them will be close to

the air and some of them have randomly

just enough energy to pop up into the

air and start floating around and be a

gas um so although the temperature of a

puddle is determined by the average

temperature of all the

particles um some particles have more

energy than others and if those

particles are found at the top of the

puddle right next to the air they may

have enough energy to sort of just sort

of bounce off the puddle and disappear

into the air so that's why puddles

evaporate if you

wondering all right so that's it for

this video uh tune in to the next video

uh which will be mixtures and pure

substances