Physical and Chemical Properties and Changes

Summary

This lesson covers the differences between physical and chemical properties and changes. Physical properties describe observable traits like color, texture, and mass, while chemical properties describe how substances react, such as flammability or oxidation. The instructor uses relatable examples, comparing chemical properties to personality traits and reactions to social situations. Physical changes involve altering appearance without forming new substances (like boiling water), while chemical changes result in new substances (like burning paper). Key concepts include precipitate formation, gas release, and temperature changes.

Takeaways

• 😀 Physical properties describe the appearance, smell, feel, and measurable characteristics of a substance.
• 👀 Examples of physical properties include color, texture, size, volume, mass, density, buoyancy, boiling point, and melting point.
• 🌡️ Chemical properties describe how a substance reacts or does not react, similar to how personality reflects behavior.
• 💥 Common chemical properties include oxidation, rusting, flammability, and reactions with other substances.
• 🧪 Physical changes involve changes in appearance or state without forming a new substance, like boiling, freezing, or crushing.
• 🔥 Chemical changes result in a new substance due to bond-breaking and rearranging of atoms, such as combustion or rusting.
• 🍎 Indicators of chemical reactions include color changes, gas formation, precipitate formation, new smells, and temperature changes.
• 📏 All phase changes, like melting, freezing, and boiling, are considered physical changes because the substance remains the same.
• ⚗️ Chemical reactions can be indicated by unexpected temperature changes or the generation of light, such as in fire or glow sticks.
• 📚 Physical and chemical properties, along with their changes, are fundamental concepts in chemistry, often seen as vocabulary.

Q & A

What is a physical property?

A physical property describes the way something looks, feels, or smells, and can sometimes be measured. Examples include color, texture, size, mass, and volume.

What is an example of a physical property?

Examples of physical properties include the rough texture of a pine cone, the brownish-red color of someone's hair, or the boiling point of water.

What distinguishes a chemical property from a physical property?

A chemical property describes how a substance reacts or does not react, which is often based on the number of valence electrons, while a physical property describes observable characteristics like size, shape, or texture.

How does the script relate chemical properties to personality traits?

The script compares chemical properties to personality traits, suggesting that just as chemical properties describe how substances react, personality traits describe how a person reacts in certain situations.

What is a physical change?

A physical change is when something changes in appearance but no new substance is formed. For example, crushing a can or freezing water are physical changes.

Can you give examples of physical changes?

Yes, examples include melting and freezing water, boiling water, breaking an object, or crushing a crystal into smaller pieces.

What is a chemical change?

A chemical change occurs when a new substance is formed due to the breaking and rearranging of chemical bonds. Examples include rusting, burning paper, and the formation of a precipitate.

What are some signs that a chemical reaction has occurred?

Signs of a chemical reaction include a color change, the formation of gas, a new smell, temperature change, or the generation of light, such as when a glow stick glows.

How is the formation of a precipitate described in the script?

The formation of a precipitate occurs when two solutions react to form a solid. An example would be mixing vinegar and baking soda, which produces gas and sometimes a solid precipitate.

What are examples of chemical properties and changes mentioned in the script?

Chemical properties mentioned include flammability and oxidation (like an apple turning brown). Chemical changes include burning paper and the reaction of vinegar with baking soda.

Outlines

00:00

👋 Introduction to Physical and Chemical Properties

The lesson begins with an introduction to physical and chemical properties. The speaker asks the viewer to list three physical and three personality traits as a warm-up exercise. Physical properties are described as characteristics that can be measured, like color, texture, size, and buoyancy. The speaker also explains how chemical properties are more related to reactivity, comparing them to personality traits. The concept of chemical properties is introduced with examples like oxidation, rusting, and reactions between substances such as vinegar and baking soda.

05:01

🍏 Oxidation, Gas Formation, and Chemical Changes

The second paragraph focuses on examples of chemical changes, starting with the oxidation of substances like apples and potatoes. It explains how gas formation occurs in reactions, using vinegar and baking soda as an example. The formation of precipitates when solutions react is also highlighted, along with the role of new smells and temperature changes as indicators of chemical reactions. The speaker also mentions light generation, like in the case of fire or glow sticks, to further illustrate chemical changes.

Keywords

💡Physical properties

Physical properties refer to characteristics of a substance that can be observed or measured without changing its chemical identity. These include aspects like color, texture, mass, volume, and boiling point. In the video, examples include the rough texture of a pine cone and the ability of a substance to float (buoyancy). These are observable qualities of materials.

💡Chemical properties

Chemical properties describe how a substance interacts or does not interact with other substances, often involving a reaction. This is likened to personality traits in the video, where the speaker talks about how substances might oxidize, corrode, or be flammable. For example, the reaction of an apple browning when exposed to oxygen is due to its chemical property of oxidation.

💡Boiling point

The boiling point is the temperature at which a substance changes from a liquid to a gas. It is a physical property and does not alter the chemical composition of the substance. In the video, it is mentioned as an example of a measurable property that can help describe a material's physical characteristics, like when water boils but remains chemically the same.

💡Oxidation

Oxidation is a chemical property that occurs when a substance reacts with oxygen, often resulting in a change in color or the formation of rust. The video uses the example of an apple turning brown when exposed to air, illustrating how oxidation is an observable chemical change that occurs over time.

💡Precipitate

A precipitate is a solid that forms when two solutions react chemically and produce a solid substance. In the video, the speaker discusses how mixing two liquids, like vinegar and baking soda, can lead to the formation of a gas, and in other reactions, a solid precipitate may form, representing a chemical change.

💡Physical change

A physical change is when a substance undergoes a transformation that affects its physical appearance or form but not its chemical composition. Examples include melting, boiling, and crushing. In the video, the speaker explains that physical changes are like verbs – actions such as bending or smashing a material – where the material's identity remains the same.

💡Chemical change

A chemical change results in the formation of a new substance due to the breaking and rearranging of chemical bonds. This is contrasted with physical changes in the video, and examples given include color changes, gas production, and temperature changes. For instance, when paper burns, it undergoes a chemical change because a new substance (ash) is formed.

💡Valence electrons

Valence electrons are the outermost electrons of an atom that are involved in chemical reactions. The number of valence electrons determines how a substance reacts with others. In the video, these are discussed as the basis for chemical properties, where the speaker compares them to personality traits that dictate how an element will react under certain conditions.

💡Phase change

A phase change is the transformation of a substance from one state of matter to another, such as from solid to liquid (melting) or liquid to gas (boiling). These are examples of physical changes. The video emphasizes that while the substance’s form may change, its chemical identity remains the same, such as ice turning to water or water turning to steam.

💡Buoyancy

Buoyancy is the ability of a substance to float in a fluid, and it is a physical property. The video uses buoyancy as an example of how physical properties can describe a material's interaction with its environment. This property is measured by comparing the substance's density relative to the fluid in which it is placed.

Highlights

Introduction to physical and chemical properties and changes.

Physical properties describe the way something looks, smells, feels, and can be measured.

Examples of physical properties include color, texture, mass, volume, and buoyancy.

Chemical properties describe how a substance reacts or does not react, often compared to personality traits.

Chemical reactions are based on the number of valence electrons in a substance.

Physical changes involve changes in form but do not create a new substance, like boiling or freezing water.

Phase changes, such as melting and freezing, are physical changes.

Chemical changes form new substances through bond-breaking and atom rearrangement.

Indicators of chemical changes include color change, gas formation, and the generation of light.

Oxidation, like apples turning brown, is a common chemical property.

Precipitate formation occurs when two solutions react to form a solid.

A new smell during a reaction, like baking bread, is a sign of chemical change.

Temperature changes in reactions, such as getting hotter or colder, are signs of chemical reactions.

Paper burning is an example of a chemical change, as new substances are formed.

Recap: Physical properties describe sensory aspects, while chemical properties describe reactivity.

Transcripts

hello welcome to this lesson on physical

and chemical properties and changes to

start off I need you to list three

characteristics about the way you look

and three characteristics of your

personality

all right a physical property is going

to describe the way that something looks

smells how it changes

um how it feels and those are going to

be properties typically that can be

measured but sometimes they are going to

be more qualitative things like

um you know my hair is kind of this

brownish red color my eyes are green I

am you know five foot six inches tall

those are things that would describe my

physical appearance those would be

physical properties

some examples of physical properties are

things like color

texture like this pine cone is very

rough

the sample size and this means in both

mass and length

um

volume any type of size is going to be a

physical property

we also have buoyancy which is it's the

substance's ability to float

the boiling point the temperature at

which the substance boils the melting

points

um and then like I said mass volume

density everything related to the

sample's size

and then we can move on to chemical

properties which is way more fun in my

opinion chemical properties describe the

way that a substance react or does not

react and that's going to be based on

the number of valence electrons now for

you and me chemical properties are kind

of like our personality so I am very

sarcastic I am also very honest almost

to a fault and I um I love to have a

good time so those are things that would

describe my personality and that's kind

of like my chemical properties so it's

going to describe the way that you react

in certain situations if you're at a

party you're probably having a good time

perhaps your idea of a good time is

sitting on the couch just watching

Netflix shows that's that's a fun time

too

um so your personality may be a little

bit more reserved

so you might be something like a noble

gas that doesn't like to react very much

it's inert

um so a chemical property is kind of

like the personality of this element or

compound

so when it comes to chemical properties

we ask ourselves questions most often

like will this substance oxidize in air

so like this apple turning brown once

it's exposed to oxygen

we would ask does it rust or corrode

when in contact with air

is that substance flammable does it

react with other chemicals which is

really what we talk about in chemistry

most often here we have the formation of

a precipitate so you mix two liquids

together two solutions really and you

wind up they react and they form a solid

here this is probably vinegar and baking

soda and that is going to generate a gas

fills the balloon

um sometimes things react and other

times things don't like baking soda in

your kitchen doesn't really react all

that much

um doesn't react with the air but it

will react with vinegar

if properties are adjectives then

physical and chemical changes are verbs

so a physical change is where a change

is made but nothing new is formed

so really this means we're not breaking

or forming bonds All Phase changes are

physical changes

so if we think of boiling or freezing

water

on the other side of that boiling or

freezing water is still water it might

just be ice or steam or something like

that

um it's going to change from one form to

another but it's still going to be water

and that's the important piece here

so like I said melting and freezing are

prime examples of physical changes so is

breaking smashing cracking boiling

another phase change crushing so if you

took a can and crushed it or if you took

a really big Crystal and crushed it down

kind of into a dust like crushing salt

into something smaller

um bending is one of course and anything

of course that is going to just change

kind of the way it looks

um is going to be a physical change now

the opposite of that is a chemical

change in a chemical change you have an

entirely new substance formed because

you have bonds breaking atoms

rearranging and new things forming and

all chemical reactions are considered

chemical changes

um it's just when we are big boy big

girl chemists a lot of the time we talk

about chemical reactions as opposed to

chemical changes it's really just the

verbiage

so a chemical change or signs in a

chemical reaction has happened is going

to be indicated by a color change

here again you have the Apple oxidizing

in air it turns brown avocados do this

potatoes there are lots of things that

will change color just because they're

exposed to oxygen

then we have formation of a gas so here

again the vinegar and baking soda is

going to fill this balloon

we have that formation of a precipitate

so anytime these two solutions come in

contact with each other they form a

solid and that solid is called a

precipitate I'll teach you a lot more

about that when we get to Solutions

um anytime you have a new smell

a new smell

um whether that is like a rotten grilled

cheese sandwich which is very yucky or

um

the baking of a cake or the baking of

bread you get this nice beautiful smell

anytime you get a new smell that's a

chemical reaction

anytime you change the temperature

if you dramatically well I shouldn't say

dramatically anytime you change the

temperature where you personally didn't

put the substance on ice or in the

fridge you didn't try to heat it up

perhaps you just mix two chemicals

together and they got really cold or

they got really hot and then another one

that's not listed here is the generation

of light so that would include fire

which is a very common light reaction

but also you have um like the cracking

of a glow stick those two chemicals come

in contact and then they start to Glow

so physical and chemical changes to

recap physical

things are

um physical properties

describe kind of with the five senses

the way that things look feel smell that

kind of thing a physical change is where

you are going to kind of rearrange the

the three-dimensional structure of this

thing you might have a piece of paper

and then rip it and now you got

two smaller pieces of paper

um that does not work with money

but it's still paper a chemical property

is going to describe the way that things

do or do not react

um and their chemical changes are really

just chemical reactions which is them

kind of expressing one of those chemical

properties so we know that paper is

flammable that's chemical property and

chemical uh the paper being on fire

would be the chemical change

that's all I have for you on physical

and chemical properties and changes I

know it was really quick but that's

because

number one it's kind of just vocabulary

two I'm sure you have learned this

before and three if it was too quick you

have the ability to go back and replay

the video please leave any questions you

have in the comments section below the

video subscribe so you don't miss the

next lesson and I will see you there bye