Introduction to the states of matter

Alright let’s get into it🥱🥱🥱🥱Thank me later🙃.

Everything is made up of very tiny particles, such as atoms, molecules and ions.

The kinetic theory of matter postulates that these particles are continually moving.

Matter basically exists in three states: Solid, Liquid and Gas.

Solids have a fixed shape and fixed volume.

Liquids have a definite volume but not a definite shape.

Gases have no definite volume or definite shape.

Remember I said that matter exists in three states, well I lied🤷‍♂️🤷‍♂️There is a fourth state.

It’s called PLASMA STATE.

Plasma is the fourth state of matter which is a high energy that we can find in sun and stars. Type plasma in ask now for more info.

Jot down what you learnt.

Change of states

Certain substances can exist as solid, liquid, and gases.

1. Solid to liquid (Melting)

2. Liquid to solid (Freezing)

3. Liquid to gas (Evaporation or Boiling)

4. Gas to liquid (Condensation)

5. Gas to solid (Deposition)

6. Solid to gas (Sublimation)

When heat is applied to substances, the particles that makes them up gains more energy to change state.

When cooled they lose energy to change state also.

Let’s go over some concepts you should know🤓.

I will only be going over 1, 2 and 3 so, study 4, 5 and 6 in ask now, sank you👌.

Melting

This is when solids gain enough energy to break the bonds binding its particles, changing into liquids.

For example, Ice to water.

Metals also melts, but at high temperatures.

The presence of impurities in a substance decreases melting point and make it gradual.

Type “how impurities decrease melting point” in ask now, If you believe you don’t understand, if you do go on.

Freezing

When heat is removed from liquids, the particles binding them loose energy, making them come closer to ach other and changing to the solid state.

Water to ice is an example or Molten lava to rocks.

Vaporization (Evaporation and Boiling)

Evaporation

This is the gradual escape of liquid particles at the surface due to the application of heat energy it receives.

Why does this happen, Evaporation happens because molecules in a liquid have different energy levels.

Some molecules at the surface gain enough kinetic energy to overcome the intermolecular forces holding them together and escape into the air as a gas (vapor).

- It is gradual.

- It is a surface phenomenon.

- It does not have a fixed temperature point for occurrence.

- Evaporation causes cooling same as boiling causes cooling.

Vaporization basically means, Change from liquid to gas. So, vaporization is the process that covers both evaporation and boiling.

The main difference is that evaporation happens gradually and only at the surface of the liquid, while boiling happens rapidly throughout the liquid when the temperature reaches a certain point.

So, note that evaporation and boiling are both forms of VAPORIZATION.

You should know these terms, Vapor pressure and Condensation.

Write them in ask now if you are not sure you know it👌I explained it there.

Latent heat of fusion and Latent heat of vaporization

Latent means hidden.

The melting point is just the temperature at which a solid turns into a liquid.

The latent heat of fusion is the energy required to actually break the solid’s bonds and turn it into a liquid at that temperature.

Let me use ice to explain better.

The melting point of ice is 0degrees.

Let’s say we have ice of 10°C – When you heat ice, its temperature goes up because the molecules vibrate faster.

At 0°C (Melting Point) – Now, things get interesting. Even though you're still adding heat, the temperature stops increasing. Why? Because all the energy is being used to break the bonds holding the ice together, not to make the molecules move faster. This is what we call latent heat of fusion.

After Melting – Once all the ice has turned into water, any extra heat starts increasing the temperature again.

So basically, heat first warms up the ice, then pauses to melt it, and then continues warming the liquid.

Latent(hidden) heat of vaporization is the heat energy that is required to change liquid to gases.

I hope😁 you learnt something, jot down what you learnt and take the first test to reinforce your knowledge.

Introduction to the study of gases

Gases obeys a kinetic molecular theory. Which are:

1. Gas particles are always continuously moving randomly in a straight line.

2. The forces holding the gas particles in a molecule are negligible.

3. Gas particles are small compared to the space between them.

4. The collision between gas molecules and the walls of the container are perfectly elastic.

5. The average kinetic energy of gas particles is directly proportional to the gas’s temperature.

Things you should know to understand the theories;

We know that gas is one of the states of matter.

We also know that gases have no fixed shape or fixed volume but they adjust to the container they are in.

Lastly you should know whenever you see PARTICLES we are talking about atoms or ions or molecules. Its just a general term.

Alright let’s gets into it😭I am crying because… I don’t know😎.

For real let’s start.

1. “Gas particles are always continuously moving randomly in a straight line”.

This theory is telling us that gas atoms are always moving just like solids and liquids,

Particles of solids vibrates, liquids can move but not to freely, but gases have little to no restriction so they move randomly without any specific orientation.

2. “The forces holding gas particles intermolecularly are negligible.”

This is telling us that, the forces holding gas molecules together are weak. Compared to solids and liquids.

3. “Gas particles are small compared to the space between them”.

This just means that because the forces holding them together are weak gases spread out and occupies a lot of space that’s why they fill up whatever container we put them.

4. “The collision between gas molecules and the walls of the container are perfectly elastic.”

Whenever you hear or see perfectly elastic it means no energy is lost.

Gases particles are of different kinetic energy and when they collide with themselves or the walls of the container, none of that kinetic energy is lost, it just bounces back.

5. “The average kinetic energy of gas particles is directly proportional to the gas’s temperature”

The higher the particles move (kinetic energy) the higher the temperature.

Or you can say

The higher the temperature (more heat) the higher the kinetic energy.

I hope you understood those five theories. It would make my efforts worth it if you do😁
Thanks.

Gas laws 1

Here we would learn about a law that tells us the relationship between pressure and volume of a gas.

What would happen to the volume of a gas if the gas pressure is increased or decreased.

Or, what would happen to the pressure of a gas if the volume is increased or decreased.

That relationship is studied and expressed in a gas law Called BOYLES LAW.

It was postulated by Rober Boyle 1662🤯.

Boyles law basically states that, the volume of a fixed mass of gas is inversely
proportional to the pressure of that gas, Given the temperature is constant.

You don’t need to cram it. In this section I will make you understand it fully. It is up to you.

Volume of a gas is how much space it occupies, and Pressure of a gas is how much force is applied to an area,
it is created when the gas particles collide with themselves and the walls of the container.

Now when they say those two properties are inversely proportional, they mean that when one of them increases the other decreases vice versa.

Meaning when volume increases, pressure decreases.

And when volume decreases pressure increases.

Let me show you how:

Mathematically, Boyles law is expressed as:

P1 x V1 = P2 x V2

P1V1 = P2V2

P1 = Initial pressure

V1 = Initial volume

P2 = Final pressure

V2 = Final volume

I hope you learnt something. In the next section we are going to work on numerous calculations to train you on the law. Are you ready?

Practice calculations on law 1 (Boyles law)

Let’s solve some problems.

Firstly, know this

Pressure is measured in atm(atmosphere) or mmHg (millimeter mercury).

1atm = 760 mmHg

There are other units but, atm and mmHg are the most common.

Secondly,

Volume is measured in L (litres) or m³ (metre cube).

There are other units but, L and m³ are the most common.

1000L = 1m³

Alright,

Problem 1

A gas occupies 4.0 L at a pressure of 2.0 atm. If the pressure is increased to 8.0 atm, what will be the new volume, assuming temperature remains constant?

Problem 2

A gas at 3.0 atm pressure occupies 10.0 L. What will be its volume if the pressure is decreased to 1.5 atm?

Problem 3

A gas has an initial pressure of 5.0 atm and a volume of 2.5 L. If the volume is changed to 1.0 L, what is the final pressure?

Problem 4

If the pressure of 10L of a gas is increased from 2.5atm to 3,040mmHg. What will be its new volume?

Problem 5

If the volume of a fixed mass of gas is doubled, what happens to its pressure?

Practice calculations on law 2 (Charles Law)

Firstly, know this:

Temperature is measured in kelvin, degree Celsius or degree Fahrenheit. K, °c and °f.

Note: Temperature must be in kelvin.

To convert Celsius to kelvin, add 273 to its value.

T = c + 273

For example;

Convert 30 °c to kelvin.

T = c + 273

T = 30 + 273 = 303k

T = 303k//

Let’s get into the problems.

Problem 1

A gas occupies 3.0 L at 27°C. What will be its volume at 127°C, assuming pressure is constant?

Problem 2

A gas at 6.5 L and 120°C expands to 9.0 L. What is the final temperature?

Problem 3

The temperature of a gas is 300k. At what temperature would its original volume be halved.

Course 4 - States of matter and Study of gases

Introduction to the states of matter

Change of states

Melting

Freezing

Vaporization (Evaporation and Boiling)

Latent heat of fusion and Latent heat of vaporization

Course 4 First Test

Introduction to the study of gases

Gas laws 1

Practice calculations on law 1 (Boyles law)

Problem 1

Problem 2

Problem 3

Problem 4

Problem 5

Gas laws 2

Practice calculations on law 2 (Charles Law)

Problem 1

Problem 2

Problem 3

Gas laws 3

Gay-Lussac’s law>