Physical Vs. Chemical Changes - Explained

Summary

In this educational video, Mr. Millings explores the distinction between physical and chemical changes. He illustrates physical changes as alterations in form without altering the substance's chemical identity, using examples like grinding peanuts into butter, folding paper into an airplane, and melting ice. Chemical changes, in contrast, involve a transformation in the substance's identity, such as fermentation of sugar to alcohol, oxidation of iron to rust, and electrolysis of water into hydrogen and oxygen. The video clarifies that all chemical changes include physical changes, but not all physical changes involve chemical alterations.

Takeaways

• 📚 Physical changes involve alterations in a substance's physical form without changing its chemical identity, such as grinding peanuts into peanut butter.
• 📈 All changes in the state of matter, like melting ice into water, are considered physical changes.
• 🔍 Physical changes are not necessarily accompanied by chemical changes, as seen when copper is turned into wire, maintaining its chemical composition.
• 🔬 Chemical changes result in a new substance with a different chemical makeup, like fermentation turning sugar into alcohol.
• 🌿 Oxidation, such as an iron nail rusting, is an example of a chemical change where the iron combines with oxygen to form a new substance.
• 🔥 Combustion, like burning logs, is a chemical change that alters the chemical composition of the material.
• 💧 Electrolysis of water, which splits it into hydrogen and oxygen gas, is a chemical change creating new substances.
• 🧀 Souring of milk is a chemical change as it breaks down into different substances over time.
• 🌡️ Sublimation of dry ice, turning it from a solid to a gas without becoming a liquid, is a physical change in state.
• 🍺 Fermentation of sugar into alcohol is a chemical change, transforming one chemical substance into another.
• 🌫️ Evaporating water, turning it into water vapor, is a physical change in state of matter.

Q & A

What is the main difference between physical and chemical changes?

Physical changes involve alterations in the physical form or state of a substance without changing its chemical identity, while chemical changes involve a transformation that results in a new substance with a different chemical makeup.

Can you give an example of a physical change from the script?

Grinding peanuts into peanut butter is an example of a physical change because the peanuts are simply changed in form, not in chemical composition.

What is the significance of the term 'ductility' mentioned in the script?

Ductility refers to the property of a metal that allows it to be stretched into a wire. In the script, turning a copper bar into copper wire demonstrates the ductility of copper.

How does the script explain the melting of ice as a type of change?

The melting of ice into liquid water is described as a physical change because it's a change in state from solid to liquid, but the chemical composition (H2O) remains the same.

What is the key takeaway from the script about changes in the state of matter?

All changes in the state of matter, such as from solid to liquid or liquid to gas, are considered physical changes because they do not involve a change in the chemical identity of the substance.

According to the script, are all physical changes accompanied by chemical changes?

No, the script clarifies that not all physical changes are accompanied by chemical changes. Physical changes can occur without altering the chemical composition of a substance.

What is an example of a chemical change given in the script?

The fermentation of sugar into alcohol is an example of a chemical change because it results in a new substance with a different chemical composition.

What process is described in the script when an iron nail turns into a 'Rusty Nail'?

The process described is oxidation, where the iron nail reacts with oxygen to form iron oxide, commonly known as rust, indicating a chemical change.

How does the script illustrate the concept of combustion as a chemical change?

The script uses the example of burning logs, where the chemical composition of the logs changes due to the combustion process, resulting in new substances.

What is electrolysis, and how does it relate to chemical changes according to the script?

Electrolysis is the process of passing an electric current through water to separate hydrogen from oxygen, creating hydrogen gas and oxygen gas. The script states that this is a chemical change because it transforms one substance into two different substances.

What is the script's final point about the relationship between physical and chemical changes?

The script concludes that while all chemical changes are accompanied by physical changes, the reverse is not true; not all physical changes involve chemical changes.

Outlines

00:00

🔄 Physical vs. Chemical Changes

This paragraph introduces the concepts of physical and chemical changes. Mr. Millings explains that physical changes involve alterations in the physical form of a substance without changing its chemical identity, using examples such as grinding peanuts into peanut butter, folding paper into an airplane, shaping copper into wire, and melting ice. He emphasizes that all changes in the state of matter, like ice melting, are physical changes and that physical changes do not involve a change in chemical composition. The paragraph concludes by noting that physical changes are not always accompanied by chemical changes.

05:01

🔬 Examples of Physical and Chemical Changes

The second paragraph delves into more examples to distinguish between physical and chemical changes. It starts by confirming that condensing water vapor is a physical change due to a change in state. Then, it discusses the combustion of gasoline as a chemical change, where gasoline is converted into different substances. The paragraph also covers the electrolysis of water into hydrogen and oxygen gases as a chemical change, the souring of milk due to the breakdown into different substances, and the sublimation of dry ice as a physical change. Additionally, it mentions turning copper into wire as a physical change due to a change in form but not in chemical composition, the fermentation of sugar into alcohol as a chemical change, and evaporating water as a physical change involving a state change from liquid to gas. The summary ends by reinforcing that all chemical changes involve physical changes, but not all physical changes involve chemical changes.

Keywords

💡Physical Change

A physical change refers to a change in the physical form or appearance of a substance without altering its chemical composition. In the video, physical changes are exemplified by grinding peanuts into peanut butter, folding paper into an airplane, and melting ice into water. These examples illustrate the concept that the identity of the substance remains the same, only its form is altered, which is central to the theme of differentiating between physical and chemical changes.

💡Chemical Change

A chemical change involves a transformation that results in a new substance with a different chemical composition from the original. The video explains chemical changes through processes like fermentation of sugar into alcohol, oxidation of an iron nail to rust, and combustion of logs. These examples are crucial to the video's theme, showing that chemical changes result in a permanent alteration of the substance's identity.

💡Identity

Identity, in the context of the video, refers to the inherent properties of a substance that define it. When discussing physical changes, the identity of the substance remains unchanged despite alterations in form. For instance, when peanuts are ground into peanut butter, their identity as peanuts is preserved, which is a key point in distinguishing between types of changes.

💡Chemical Makeup

Chemical makeup denotes the composition of elements, molecules, or compounds that constitute a substance. The video emphasizes that physical changes do not involve a change in the chemical makeup, whereas chemical changes do. For example, the melting of ice is a physical change because the chemical makeup of H2O remains the same.

💡Ductility

Ductility is the property of a metal that allows it to be drawn out into a thin wire without breaking. In the video, the process of turning a copper bar into copper wire demonstrates ductility. This concept is used to illustrate a physical change where the metal's form changes but its chemical composition remains constant.

💡State of Matter

The state of matter refers to the distinct conditions in which matter can exist, such as solid, liquid, or gas. The video script explains that all changes in state of matter, like melting ice or evaporating water, are physical changes because they involve a change in form rather than in chemical composition.

💡Fermentation

Fermentation is a biological process that converts sugar into alcohol, often by the action of microorganisms. The video uses fermentation as an example of a chemical change, where the original substance (sugar) is transformed into a different substance (alcohol), altering its chemical makeup.

💡Oxidation

Oxidation is a chemical reaction in which a substance combines with oxygen. In the video, the rusting of an iron nail is described as an example of oxidation, where the iron reacts with oxygen in the air to form iron oxide, a new substance with a different chemical makeup.

💡Combustion

Combustion is a chemical reaction that occurs when a substance reacts rapidly with oxygen, producing heat and often light in the form of a flame. The video script mentions the burning of logs as an example of a chemical change, where the original substances are transformed into different products like carbon dioxide and water.

💡Electrolysis

Electrolysis is a process that uses an electric current to drive a non-spontaneous chemical reaction. In the context of the video, the decomposition of water into hydrogen and oxygen gases through electrolysis is a chemical change, as it results in the formation of new substances from the original water molecules.

💡Sublimation

Sublimation is the transition of a substance directly from the solid to the gas phase without passing through the intermediate liquid phase. The video script uses the sublimation of dry ice as an example of a physical change, where the state of the substance changes but its chemical identity as carbon dioxide remains the same.

Highlights

Introduction to the concept of physical versus chemical changes.

Definition of physical changes as alterations that do not affect the substance's chemical identity.

Example of grinding peanuts into peanut butter as a physical change.

Folding paper into an airplane illustrates a physical change without altering chemical makeup.

Explanation of ductility as the ability to turn metals like copper into wire, a physical change.

Melting ice to water as an example of a physical change, maintaining the chemical composition of H2O.

All changes in state of matter are identified as physical changes.

Clarification that physical changes do not necessarily involve chemical changes.

Introduction to the concept of chemical changes involving a change in the substance's identity or chemical makeup.

Fermentation as a chemical change turning sugar into alcohol, a different substance.

Oxidation of an iron nail turning it into rust, a chemical change.

Combustion or burning as a process that results in a chemical change.

Electrolysis of water into hydrogen and oxygen gas as a chemical change.

All chemical changes are accompanied by physical changes, but not vice versa.

Examples provided to distinguish between physical and chemical changes.

Condensation of water vapor as a physical change due to a change in state of matter.

Combustion of gasoline as a chemical change involving the conversion of gasoline into different substances.

Electrolysis of water as a chemical change resulting in two different substances.

Souring of milk as a chemical change due to the breakdown into different substances.

Sublimation of dry ice as a physical change, transitioning from solid to gas without becoming a liquid.

Turning copper into wire as a physical change with no change in chemical composition.

Fermentation of sugar into alcohol as a chemical change, transforming one chemical substance into another.

Evaporation of water as a physical change, changing from liquid to gas.

Conclusion summarizing the differences between physical and chemical changes.

Transcripts

[Music]

hey you guys this is Mr millings and

today we're going to talk about physical

versus chemical changes so what are

physical changes well it says right here

that physical changes are changes in a

substance that do not involve a change

in the Identity or chemical makeup of

that substance so let's take a look at a

few examples here down below let's

suppose we have some peanuts and what

we're going to do is we're going to

grind these peanuts down to make peanut

but

we still have peanuts here and we still

have peanuts here it's just taken on a

different physical form so this is going

to be a physical change this would be

example of a physical change right here

grinding peanuts into peanut butter

let's take a look at this piece of paper

right here if we fold this piece of

paper up to make a paper airplane this

would be an example of a a physical

change we're not changing the chemical

makeup of the paper we're simply

changing its physical appearance over

here if we take a look at this copper

bar right here what we're going to end

up doing is we're going to end up

turning this into copper wire and

anytime you can take a metal and turn it

into wire that uh that that shows that

that that metal is

ducal okay ducal is the process or

ductility is the process of turning uh

metal into wire so we still have copper

here and it's still copper here it's

just taking on a different physical form

let's take a look right here we have ice

which we know is

H2O that's water in the solid stage or

state and what we're going to do with

this ice is we're going to melt it down

into liquid water so it's still H2O here

we did not change the chemical makeup of

this uh we just changed the physical

appearance so this too would be a

physical change all right so once again

changes in a substance that do not

involve a change in the Identity or

chemical makeup of that substance are

physical changes and it's important to

keep in mind and this is very important

that all changes in state of matter are

going to be physical changes so anytime

you go from solid to liquid or liquid to

gas or gas to liquid and liquid back to

solid it's going to be a physical change

just like the ice melting over here that

is going to be a physical change all

right lastly it says all physical

changes are not necessarily accompanied

by a chemical change and we'll talk

about chemical changes in a second but

understand that when we when we take

these peanuts and make peanut butter out

of it we're not changing the chemical

composition okay this is only going to

be a physical change same right here

same thing right here and same thing

right here okay okay so now let's take a

look at chemical

changes okay it says right

here that chemical

changes are changes in a substance that

do involve a change in the Identity or

chemical makeup of that substance so if

we take a look here if we have some

sugar here and we end up making some

type of alcohol over here that process

is called fermentation fermentation is

the process of turning sugar into

alcohol so we have sugar over here which

is one type of compound and we have

alcohol over here which is a totally

different substance and so that is going

to be a chemical change another example

right here if we have an iron nail and

we leave it out uh on the grass

overnight uh it might turn into this

Rusty Nail over time right that process

is called oxidation right uh the iron

nail here the iron is combining with

oxygen to produce uh some iron oxide or

rust over here that is going to be a

chemical change the chemical composition

position of this nail now is different

than when than what we started with if

we take a look right here we have some

logs here and if we light these logs on

fire like we see right here this will be

an example of a chemical change right

this is going to be a chemical change

anytime we burn something or anytime

there's some sort of combustion going on

that's going to be a chemical change

we're changing the chemical composition

of these of these logs if we take a look

right here if we take some water which

is uh made of of two hydrogen's bonded

to one oxygen and we pass an electric

current through it what ends up

happening is the

hydrogen the hydrogens break free from

the oxygen and end up producing hydrogen

gas and oxygen gas okay so we have one

substance over here which is water and

we have two brand new substances over

here which is hydrogen gas and oxygen

gas and this too would be an example of

a chemical change okay so one last thing

that you need to keep in mind and this

is very important as well it says right

here that all chemical changes are

accompanied by physical changes so

primarily all of these are going to be

examples of chemical changes but there's

a physical change also if you take a

look there's a physical change in the

appearance here there's a physical

change in the appearance of these logs

there's a physical uh change in the

appearance of the iron nail there's a

physical change in the appearance of

this water so all chemical changes are

accompanied by a uh physical change but

the opposite is not true not all

physical changes are accompanied by

chemical changes okay so here are some

examples of physical and chemical

changes let's now take a look at a few

more and see if you can determine which

is

which okay so let's just quickly go

through each one of these examples here

and what we need to do is determine if

it is a physical or chemical change and

once again we will assume that all

chemical changes are also physical

changes so right here if we have

condensing water vapor so that's water

vapor that is turning back to a liquid

that is a change in state of matter that

will always be a physical

change let's look at this next one the

combustion of gasoline okay so when gas

gasoline catches on fire what's

happening is that there's a chemical

change going on that gasoline is being

converted into something else or

something totally different so this will

be an example of a chemical change let's

look at this next one turning water into

hydrogen and oxygen gas we just talked

about electrolysis and anytime you're

turning one thing

or one chemical into two different

chemicals or one substance into two

different substances that's going to be

a chemical change as

well let's look at this one milk souring

so over time what happens is that milk

is breaking down and it's being

converted into different substances so

that's going to be a chemical

change let's look at this one the

sublimation of dry ice so sublimation

that's the process of going from a solid

directly to a gas without passing the

liquid stage first and in a different

video we talked about that so that's

going to be a change in state of matter

and that's going to be a physical change

remember all changes in states of matter

are always physical changes what about

turning copper into wire turning copper

into wire it's still going to be copper

it just has a different physical form so

that is a physical change as well let's

look at this one the fermentation of

sugar into alcohol we talked about this

uh few moments ago we are turning sugar

into something totally different we're

turning one chemical substance into a

different chemical substance so that

will be a chemical

change and last but not least we have

evaporating water evaporating tells you

that that liquid is turning into a gas

in this case water vapor so that is

going to be a change in state of matter

and all changes in state of matter are

physical

changes okay so that's physical and

chemical changes in a nutshell if you

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and I hope this was

helpful