C10 - WHOLE TOPIC GCSE ORGANIC CHEMISTRY (GCSE CHEMISTRY ONLY)

Summary

This educational video delves into organic chemistry, focusing on carbon-containing molecules like esters, alcohols, and alkenes. It explains alkene reactivity due to double bonds, contrasting it with saturated alkanes. The video covers how alcohols are made through fermentation, their combustibility, and how they form alkalis with alkaline metals. It also discusses oxidation of alcohols to carboxylic acids, the weak acidic nature of carboxylic acids, and ester formation with their characteristic smells. The lesson aims to simplify complex organic reactions for better understanding.

Takeaways

• 🌐 Organic chemistry focuses on molecules containing carbon.
• 🔍 Alkenes are more reactive than alkanes due to their double bonds.
• 🧪 The bromine test is used to identify alkenes, changing color from orange to colorless.
• ➕ Alkenes can undergo addition reactions, such as with bromine or hydrogen.
• 📝 The molecular formula for ethene (an alkene) is C2H4.
• 🍾 Alcohols contain the -OH functional group and are key in fermentation processes.
• 🔥 Alcohols are highly combustible, producing carbon dioxide and water upon combustion.
• 🧪 Alcohols react with alkaline metals to form strong alkalis, like sodium ethoxide.
• 🍇 Oxidation of alcohols can lead to the formation of carboxylic acids, affecting taste in beverages.
• 🍎 Esters have distinctive smells and are formed through the reaction of an alcohol with a carboxylic acid.
• 📖 Naming esters involves placing the alcohol name first, followed by the carboxylic acid with 'oate' at the end.

Q & A

What is the main focus of the video script?

The video script focuses on explaining organic reactions involving molecules that contain carbon, such as esters, alcohols, and alkenes.

Why are alkenes more reactive than alkanes?

Alkenes are more reactive than alkanes because they contain double bonds, which means their carbons are not saturated and can readily undergo addition reactions.

What happens when bromine is added to an alkene?

When bromine is added to an alkene, an addition reaction occurs where the bromine atoms add across the double bond, resulting in a color change from orange to colorless.

How can you convert an alkene back to an alkane?

An alkene can be converted back to an alkane by adding hydrogen to it, a process known as hydrogenation.

What is the molecular formula for ethene?

The molecular formula for ethene is C2H4.

What is the general formula for alkenes?

The general formula for alkenes is CnH2n.

What is the functional group present in alcohols?

The functional group present in alcohols is the hydroxyl group (OH).

How are alcohols typically produced?

Alcohols are typically produced through a process called fermentation.

What happens when an alcohol is oxidized?

When an alcohol is oxidized, it can become a carboxylic acid, which can give a musty or vinegary taste.

What is the molecular formula for ethanol?

The molecular formula for ethanol is C2H6O.

How do esters get their distinctive smells?

Esters have distinctive smells due to their chemical structure, which can vary widely, leading to different odors such as those resembling fruits.

What reaction is used to make esters?

Esters are made through the reaction of an alcohol with a carboxylic acid, resulting in the formation of an ester and water.

How are esters named in organic chemistry?

Esters are named by taking the name of the alcohol and placing it first, followed by the name of the carboxylic acid with the 'oic' ending replaced by 'oate'.

Outlines

00:00

🔬 Organic Reactions and Carbon Molecules

The video script introduces organic chemistry, focusing on molecules containing carbon such as esters, alcohols, and alkenes. The instructor explains how these molecules react differently due to the presence of functional groups. Alkenes are highlighted for their reactivity due to the presence of double bonds, which allow for addition reactions. The instructor demonstrates how alkenes can be tested with bromine, which turns from orange to colorless upon reaction, and how alkenes can be converted back to alkanes by adding hydrogen. The importance of alkenes in industry due to their reactivity is emphasized. The script also briefly mentions the molecular formulas for alkenes and introduces other functional groups like alcohols, carboxylic acids, and esters.

05:03

🍷 Alcohols: Properties, Reactions, and Fermentation

This section delves into the properties and reactions of alcohols. Alcohols are described as highly combustible, capable of producing carbon dioxide and water upon combustion. They can also form strong alkalis when reacted with alkaline metals. The script explains the fermentation process, crucial for producing consumable alcohols and hand sanitizers. It also covers the oxidation of alcohols, which can lead to the formation of carboxylic acids if left exposed to air or treated with an oxidizing agent like potassium dichromate. The importance of sealing alcohol containers to prevent oxidation and the resulting musty taste is highlighted. The script also touches on the weak acidic nature of carboxylic acids and their reactions with bases and metal carbonates.

10:03

🍎 Esters: Formation, Naming, and Distinctive Smells

The final paragraph discusses esters, which have distinctive smells that can range from sweet to fruity. The instructor explains how esters are formed through a reversible reaction between an alcohol and a carboxylic acid, resulting in an ester and water. The script provides an example of ester formation using ethanol and propanoic acid to produce ethyl propanoate and water. The process of naming esters is also covered, where the alcohol part is mentioned first, followed by the carboxylic acid part. The instructor encourages viewers to engage with esters in a lab setting to experience their diverse aromas and concludes the video with a call to like and subscribe for more content.

Keywords

💡Organic Chemistry

Organic chemistry is a branch of chemistry that focuses on carbon-containing compounds. In the video, the science teacher introduces organic chemistry as the study of molecules containing carbon, which is central to understanding the various reactions and properties discussed throughout the lesson.

💡Alkenes

Alkenes are unsaturated hydrocarbons with at least one carbon-carbon double bond. The video explains that alkenes are more reactive than alkanes due to their double bonds, which allow for addition reactions. An example given is the reaction of ethene with bromine, which results in a color change from orange to colorless, indicating the presence of alkenes.

💡Functional Groups

Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The video discusses how changing functional groups can alter the properties and reactivity of molecules, such as in alkenes, alcohols, and carboxylic acids.

💡Esters

Esters are organic compounds that consist of a carbon atom double-bonded to an oxygen atom, with the other two of the carbon's bonds being single bonds to a carbonyl group and an alkyl or aryl group. The video mentions esters as an example of a functional group and discusses their formation through the reaction of an alcohol with a carboxylic acid.

💡Alcohols

Alcohols are organic compounds with one or more hydroxyl (-OH) groups attached to a carbon atom. The video describes ethanol as an example of an alcohol, which is found in beverages and can be produced through fermentation. Alcohols are noted for their combustibility and ability to form alkalis with alkaline metals.

💡Carboxylic Acids

Carboxylic acids are organic compounds that contain a carboxyl group (-COOH). The video explains that carboxylic acids, such as ethanoic acid, are weak acids that do not fully dissociate in water, which is demonstrated by their reversible reaction with water to form hydrogen ions.

💡Fermentation

Fermentation is an anaerobic process that converts sugar to alcohol and carbon dioxide. The video describes fermentation as the process used to make alcoholic beverages and hand sanitizers, emphasizing its importance in producing alcohols like ethanol.

💡Oxidation

Oxidation is a chemical reaction that involves the loss of electrons or an increase in oxidation state. In the context of the video, oxidation is discussed as a reaction where an alcohol can be converted into a carboxylic acid, such as the oxidation of propanol to propanoic acid, which can give a musty or vinegary taste if the alcohol is left exposed to air.

💡Combustion

Combustion is a chemical reaction between a substance and an oxidant, usually accompanied by the production of heat and light. The video mentions that alcohols are highly combustible, producing carbon dioxide and water as byproducts, similar to the combustion of alkanes.

💡Naming Conventions

Naming conventions in organic chemistry are systematic ways of assigning names to chemical compounds. The video touches on the naming of esters, where the alcohol part is mentioned first, followed by the carboxylic acid part, with specific suffixes indicating the type of compound.

Highlights

Organic chemistry focuses on molecules containing carbon.

Different molecules with carbon such as esters, alcohols, and alkenes are discussed.

Reactions of these molecules are defined by other elements combined with carbon.

Alkenes are more reactive due to their double bonds and can add substances to their carbons.

Bromine's reaction with alkenes is used as a test, changing color from orange to colorless.

Alkanes are saturated and less reactive compared to alkenes.

Alkenes' reactivity makes them more useful in industry for modifying carbon structures.

Alkenes follow the general formula CnH2n.

Alcohols contain an OH functional group and are highly combustible.

Ethanol, a common alcohol, is found in beverages and has the molecular formula C2H6O.

Carboxylic acids have the functional group COOH and include ethanoic acid.

Esters have a generic formula with C-O-O-R and ethyl ethanoate is an example.

Alcohols can be produced through fermentation, a process used in beverages and hand sanitizers.

Alcohols react with alkaline metals to form strong alkalis, such as sodium ethoxide.

Oxidation of alcohols can produce carboxylic acids, affecting the taste of wines if left open.

Carboxylic acids are weak acids and do not fully dissociate in water.

Esters have distinctive smells and can be made by reacting an alcohol with a carboxylic acid.

Naming esters involves placing the alcohol name first, followed by the acid name.

Transcripts

hi guys it's your science teacher here

back with another video

this time is all about organic reactions

organic chemistry is a specific type of

chemistry

looking into molecules that contain

carbon

and in today's lesson what we're going

to do is we're going to look at

different

molecules that contain carbon such as

esters

alcohols and alkenes and look

how they react their reactions are

actually defined by other things

combined

in there other than carbon as well so

we're going to have a look at

how changing functional groups can uh

mess up the properties

and make them react a bit differently

here i've got an alkene and i can tell

i've got an alkene because of the double

bonds okay

if i was to do it properly i'd actually

add my hydrogens on

and that's now ethene um

and alkenes are more interesting than

alkanes because the fact

the double bond means they're more

reactive i can add things onto them

carbons they are not saturated

like alkanes meaning all the carbons are

used up in bonding

so this makes them highly reactive and i

can add things

to the double bonds okay

for example here's his generic reaction

just x and y but

i could substitute that in for a real

molecule such as bromine for example

and this is the reaction we use to test

for alkenes

because bromine on its own is

orange and you you might remember that

from looking at bromine water in a lab

and when you add that to ethene what

happens is

the bromine will add on where the double

bond was

and now i have

dibromoethane antibromoethane is

actually colourless so in this reaction

you would see a change in colour going

from orange

to colourless it isn't just bromine i

can add

to my carbons i could also add hydrogen

if i wanted to and convert it straight

back to being an alkane

and that would just like they look like

this with me making

ethane instead but because of the

alkenes reactivity

that makes them a lot more useful than

alkanes because i can change what is on

my carbons whereas i can't do that with

my alkanes remember

that that is saturated it's hard to

control where i add my functional groups

if i've got

functional groups which i want to add so

that's why alkenes are often more useful

in industry

so so far we've looked at alkenes and we

know that an

alkene has the formula c double bond

c and we'll just draw ethane just for an

example

uh here and the molecular formula

for that would look c2h4 that's how

you'd write it out

remember that alkenes have the general

rule of

cnh2 like that

but we aren't just going to stop at

alkenes we're going to learn about some

other

functional groups and the first one

we're going to look at is alcohols

and alcohols have the functional group

o h onto the chain

so if i was to draw an alcohol i'll draw

ethanol which is

alcohol the stuff that you find in

beverages all over the country it looks

like that and this is just ethanol that

i've drawn out

ethanol would have the molecular formula

c2 h6o

we don't just stop at alcohols either

we're going to look at carboxylic acids

as well

and carboxylic acids have

the generic addition of cooh

and what that looks like in real life is

this double bond o o h

and then this is actually ethanoic

acid and what that would look like

written down as a molecular formula

is c2 h4

and the last one we're going to look at

is esters

which have the generic formula with c

o o r and i'll tell you what the r group

stands for

i'll draw out the formula of ethyl

ethanoate

which should look like this c h h

h c and then there's a double bond up

here

and then there's a single bond to an

oxygen here and then the chain continues

c

h2 and then ch3

like that and writing out the molecular

formula

would just look like this c for

h eight and then

o two

and i'll go over how to name esther's a

little bit later on in the video

they're quite tricky to name

we're going to look at alcohols now and

we're going to look at

how they react and how we can make

alcohols as well so we can make alcohols

using a process called

fermentation and this is the process we

use

in order to make alcohol that we consume

in beverages or that we use in hand

sanitizers so fermentation

is an incredibly important process

alcohols have a few really cool

properties as well one being that

they're highly combustible

that means that they burn very well and

generically

from the combustion we will make the

products

carbon dioxide and water

just like when we were looking

at alkanes and combusting them as well

you can also make some pretty strong

alkalis

using alcohols as well um

alcohols react similarly with to water

when you add an alkaline metal with them

and it will make a strong alkaline

when you add a alcohol

to it um now the naming of it it would

be a

sodium

alkoxide for example if i was to add

ethanol to sodium it would make sodium

ethoxide

and my other product is hydrogen

gas

the last reaction we're going to look at

is one called oxidation

and if we leave an alcohol

uh in the air actually it will

uh become oxidized however you could

speed this uh reaction up by adding an

oxidizing agent like potassium

dichromate

and what this oxidation will produce is

a carboxylic acid

this is why when you have an alcohol

you have to put the lid back on uh say

if you had wine

you put the lid back on because of the

fact it will become a carboxylic acid if

you leave it out and that's what gives a

wine kind of like a musty taste

so that's why it's important for wine

manufacturers to make sure their lids

are sealed tight

and that's why people taste the wine

before their meal is because of the fact

um if it's become too oxidized it will

start to taste

like ethanoic acid the vinegary taste

you don't have to remember all the

balanced equations for these reactions

you just have to remember

the general scheme of these reactions so

an alcohol

if it's oxidized will become acids

and an example would be if i had

propanol and i left it out in the air or

added potassium dichromate

i would get propanoic acid

carboxylic acids are known as weak acids

because they do not

fully dissociate what that means

is that they do not fully dissociate to

make h plus ions if i was to show you

what i mean by that if i draw out

uh ethanoic acid and

what happens when you add ethanoic acid

to water

is this uh reversible reaction

and it produces h plus ions however

it doesn't fully go all the way uh to

the right the reaction it's reversible

and ethanoic acid is reformed and so the

h

plus is not fully dissociated and that's

why it's known as

a weak acids carboxylic

acids will react like usual acids if i

add

my carboxylic acid to a base uh

if i had it to say a metal carbonate

then

uh what i'll get is the same type of

reaction

i will make my salt which would be in

this case

ch3coo

i will make water and i will also make

carbon dioxide because if you add a

metal carbonate

to an acid these are always my products

and all i need to do to balance this

equation

actually is just put two in front of

each one of them

esther's are really cool because they

have a distinctive smells you can um

actually maybe in a lab your teachers

might have

let you smell some different esters they

often have quite sm

sweet smells uh they're often very

different from one another some esters

smell like

apples some like pears so they're really

fun to actually play with in the lab

and to make an esther what you need to

do is you need to have an alcohol

and add it to a carboxylic acid

and you make for yourself

a ester and water and this is a

reversible reaction if you add an ester

to water you will make

a carboxylic acid and an alcohol so

let's see what one of these

reactions would look like in real life

if i had ethanol for example and i was

added to

propanoic acids what i would

make ethyl propanoate and

water and i said i'd talk to you a bit

about how to name

esters so i'll do that now what you do

is you take

the alcohol and that always goes at the

start with isle at the end

and then you take your carboxylic acid

and that goes at the end with 08 at the

end

i'll just do one more example so you can

see what i mean if i have butanol

and i have ethanoic acid

this time what i will make is

butyl

ethanoa and water

thank you for watching this screencast

uh i hope you enjoyed the video

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