Single-Bonded Functional Groups
When you cut yourself, it is often a good idea to swab the cut with rubbing alcohol to disinfect it. Most rubbing alcohols that are sold in drugstores are based on 2-propanol (common name: isopropanol), C3H8O. You can also swab a cut with a rubbing alcohol based on ethanol, C2H6O. Often it is hard to tell the difference between these two compounds. Both have a sharp smell, and both evaporate quickly. Both are effective at killing bacteria and disinfecting wounds. What is the connection between these compounds? Why is their behaviour so similar?
Functional Groups
Both 2-propanol and ethanol contain the same functional group, an OH (hydroxyl) group, as shown in Figure 1.12. Because ethanol and 2-propanol have the same OH functional group, their behaviour is similar.
The general formula for a family of simple organic compounds is R + functional group. The letter R stands for any alkyl group. (If more than one alkyl group is present, R′ and R′′ are also used.) For example, the general formula ROH refers to any of the following compounds: CH3OH, CH3CH2OH, CH3CH2CH2OH, CH3CH2CH2CH2OH, etc.
Organic compounds are named according to their functional group. Generally, the suffix of a compound’s name indicates the most important functional group in the molecule. For example, the suffix -ene indicates
the presence of a double bond, and the suffix -ol indicates the presence of a hydroxyl group.
Functional groups are a useful way to classify organic compounds, for two reasons: 1. Compounds with the same functional group often have similar physical properties. In the next two sections, you will learn to recognize various functional groups. You will use functional groups to help you predict the physical properties of compounds.
2. Compounds with the same functional group react chemically in very similar ways. In Chapter 2, you will learn how compounds with each functional group react.
Table 1.4, on the next page, lists some of the most common functional groups.
Physical Properties and Forces Between Molecules
Organic compounds that have the same functional group often have similar physical properties, such as boiling points, melting points, and solubilities. Physical properties are largely determined by intermolecular forces, the forces of attraction and repulsion between particles. Three types of intermolecular forces are introduced below. You will examine
these forces further in Chapter 4.
• Hydrogen bonding is a strong intermolecular attraction between the hydrogen atom from an NH, OH, or FH group on one molecule, and a nitrogen, oxygen, or fluorine atom on another molecule.
• The attractive forces between polar molecules are called dipole-dipole interactions. These forces cause polar molecules to cling to each other.
• Dispersion forces are attractive forces that occur between all covalent molecules. These forces are usually very weak for small molecules, but they strengthen as the size of the molecule increases.
The process that is outlined on the next page will help you to predict the physical properties of organic compounds by examining the intermolecular forces between molecules. As you progress through the chapter, referring back to this process will enable you to understand the reasons behind trends in physical properties.
In the following ThoughtLab you will use the process in the box above to predict and compare the physical properties of some organic compounds.
Compounds With Single-Bonded Functional Groups
Alcohols, alkyl halides, ethers, and amines all have functional groups with single bonds. These compounds have many interesting uses in daily life. As you learn how to identify and name these compounds, think about how the intermolecular forces between their molecules affect their properties and uses.
Alcohols
An alcohol is an organic compound that contains the OH functional group. Depending on the position of the hydroxyl group, an alcohol can be primary, secondary, or tertiary. Figure 1.13 gives some examples of alcohols.
Table 1.6 lists some common physical properties of alcohols. As you learned earlier in this chapter, alcohols are polar molecules that experience hydrogen bonding. The physical properties of alcohols depend on these characteristics.
Additional Characteristics of Alcohols
• Alcohols are extremely flammable, and should be treated with caution.
• Most alcohols are poisonous. Methanol can cause blindness or death
when consumed. Ethanol is consumed widely in moderate quantities, but it causes impairment and/or death when consumed in excess.
Alkyl Halides
An alkyl halide (also known as a haloalkane) is an alkane in which one or more hydrogen atoms have been replaced with halogen atoms, such as F, Cl, Br, or I. The functional group of alkyl halides is RX, where X represents a halogen atom. Alkyl halides are similar in structure, polarity, and reactivity to alcohols. To name an alkyl halide, first name the parent hydrocarbon. Then use the prefix fluoro-, chloro-, bromo-, or iodo-, with a position number, to indicate the presence of a fluorine atom, chlorine atom, bromine atom, or iodine atom. The following Sample Problem shows how to name an alkyl halide.
Ethers
Suppose that you removed the H atom from the OH group of an alcohol. This would leave space for another alkyl group to attach to the oxygen atom.
The compound you have just made is called an ether. An ether is an organic compound that has two alkyl groups joined by an oxygen atom.
The general formula of an ether is ROR. You can think of alcohols and ethers as derivatives of the water molecule, as shown in Figure 1.14.
Figure 1.15 gives two examples of ethers.
To name an ether, follow the steps below. The Sample Problem then shows how to use these steps to give an ether its IUPAC name and its common name.
How to Name an Ether
IUPAC Name
Step 1 Choose the longest alkyl group as the parent alkane. Give it an alkane name.
Step 2 Treat the second alkyl group, along with the oxygen atom, as an alkoxy group attached to the parent alkane. Name it by replacing
the -yl ending of the corresponding alkyl group’s name with -oxy. Give it a position number.
Step 3 Put the prefix and suffix together: alkoxy group + parent alkane.
Common Name
Step 1 List the alkyl groups that are attached to the oxygen atom, in alphabetical order.
Step 2 Place the suffix -ether at the end of the name.
Table 1.7 describes some physical properties of ethers. Like alcohols, ethers are polar molecules. Ethers, however, cannot form hydrogen bonds with themselves. The physical properties of ethers depend on these characteristics.
Amines
An organic compound with the functional group -NH2, -NHR, or -NR2 is called an amine. The letter N refers to the nitrogen atom. The letter R refers to an alkyl group attached to the nitrogen. The general formula of an amine is R-NR′2. Amines can be thought of as derivatives of the ammonia molecule, NH3. They are classified as primary, secondary, or tertiary, depending on how many alkyl groups are attached to the nitrogen atom. Note that the meanings of “primary,” “seconday,” and “tertiary” are slightly different from their meanings for alcohols.
Figure 1.16 gives some examples of amines.
To name an amine, follow the steps below. The Sample Problem illustrates how to use these steps to name a secondary amine.
How to Name an Amine
Step 1 Identify the largest hydrocarbon group attached to the nitrogen atom
as the parent alkane.
Step 2 Replace the -e at the end of the name of the parent alkane with
the new ending -amine. Include a position number, if necessary, to
show the location of the functional group on the hydrocarbon chain.
Step 3 Name the other alkyl group(s) attached to the nitrogen atom. Instead
of position numbers, use the letter N- to locate the group(s). (If two
identical alkyl groups are attached to the nitrogen atom, use N,N-.)
This is the prefix.
Step 4 Put the name together: prefix + root + suffix.
Amines are polar compounds. Primary and secondary amines can form hydrogen bonds, but tertiary amines cannot. Table 1.8 lists some common physical properties of amines.
Additional Characteristics of Amines
• Amines are found widely in nature. They are often toxic. Many amines that are produced by plants have medicinal properties.
(See Figure 1.17.)
• Amines with low molecular masses have a distinctive fishy smell. Also, many offensive odours of decay and decomposition are caused by amines. For example, cadavarine, H2NCH2CH2CH2CH2CH2NH2, contributes to the odour of decaying flesh. This compound gets its common name from the word “cadaver,” meaning “dead body.”
• Like ammonia, amines act as weak bases. Since amines are bases, adding an acid to an amine produces a salt. This explains why vinegar and lemon juice (both acids) can be used to neutralize the fishy smell of seafood, which is caused by basic amines.
Who’s who in the office
Listen to two people talking about the people in their office to practise and improve your listening skills.
Do the preparation task first. Then listen to the audio and do the exercises.
Preparation
See MoreListening A2: Who’s who in the office – preparation
Match the words and the definitions.
Transcript
See MoreJani: Welcome to the department, Yuki. Let me show you around and tell you about your new colleagues. I’ll introduce you to them all later.
Yuki: Great. Thanks. So, who are those people over there?
Jani: That’s the order management team. Luciana deals with the new orders. She’s the one with short, dark hair.
Yuki: In the purple dress?
Jani: Yeah, that’s right. You’ll probably work closely with her while you are learning about our ordering process.
Yuki: Got it, thanks. And who’s that over there? The guy who’s on the phone?
Jani: Oh, you mean the one by the window? In the green shirt? Ah, that’s Ian. He’s the marketing director. And that’s Maria beside him. She’s responsible for the internal IT systems.
Yuki: OK, I’ll try to remember all of this. I should probably be taking notes!
Jani: Don’t worry about it. For now it’s just good to put some faces to names.
Yuki: OK, great – and who do I talk to about setting up my mobile phone with email access? Is that also Maria?
Jani: No, you need to talk to Sebastian who works in communications. He can help you. That’s him over there, next to the printer.
Yuki: Thanks. I’ll introduce myself to him later.
Task 1
See MoreListening A2: Who’s who in the office – 1
Are the sentences true or false?
Task 2
See MoreListening A2: Who’s who in the office – 2
Match the two halves of the sentence.
Understanding an explanation
Listen to a professor’s explanation to practise and improve your listening skills.
Do the preparation task first. Then listen to the audio and do the exercises.
Preparation
See MoreListening A2: Understanding an explanation – preparation
Match the words and the definitions.
Trascript
See MoreProfessor: OK, before we continue, does anybody have a question? Oh, lots of questions, I see. OK, we’ll go one at a time. Yes?
Student: Thank you. You talked about Fibonacci numbers in the lecture. Sorry, I don’t understand. Can you explain?
Professor: Of course. What do you want to know?
Student: OK … I hope this isn’t a silly question, but what does Fibonacci actually mean?
Professor: No question is ever silly – it’s always good to ask. OK, it’s the name of a person. Fibonacci was a European mathematician in the Middle Ages.
Student: Ah, OK. Thanks. So, we know he was a person, but what are the Fibonacci numbers? I don’t get it.
Professor: The Fibonacci numbers are a sequence of numbers. They go 1, 1, 2, 3, 5, 8 and so on. Do you see the sequence? Do you see how it works?
Student: I’m not sure.
Professor: OK. This is how it works. The first number is 1, then 1 again, then 2. The third number is the first number plus the second number. The fourth number is the second number plus the third number: 1 plus 2 is 3. The fifth number is the third number, 2, plus the fourth number, 3. So the fifth number in a Fibonacci sequence is 5.
Student: Ah! I think I understand now. But what about their importance? You said these were very important.
Professor: Yes, let me explain. This sequence of numbers is important because we see it in many things. Fibonacci numbers are common in geometry, they are common in nature, for example in plants. We see the sequence everywhere.
Student: Could you give us some more examples?
Professor: OK … well, we don’t have time right now but I can bring more examples in for next class, OK?
Task 1
See MoreListening A2: Understanding an explanation – 1
Choose the correct answer.
Task 2
See MoreListening A2: Understanding an explanation – 2
Put the words in order.
Transport announcements
Listen to some transport announcements to practise and improve your listening skills.
Do the preparation task first. Then listen to the audio and do the exercises.
Preparation
See MoreListening A2: Transport announcements – preparation
Match the definitions with the words in CAPITAL letters in the sentences.
Transcript
See MoreA
The next train to arrive at Platform 2 is the 12.20 to Bristol Temple Meads, calling at Reading, Oxford and Bristol Parkway. Platform 2 for the 12.20 to Bristol. First class is in the rear carriage.
B
This is a platform announcement for passengers for the 12.20 service to Bristol Temple Meads. This train is delayed by approximately 8 minutes. The train will now depart from Platform 9. Passengers for the 12.20 train to Bristol, please make your way to Platform 9.
C
Passengers for Flight EB380 to Paris please make your way to Gate 13 for boarding. Gate 13 for flight EB380 to Paris. Please have your passports and boarding passes ready. Your flight is ready to board.
D
This is a London Underground service to Liverpool Street. The next station is Liverpool Street. Upon arrival, the first set of doors will not open. Customers in the first carriage, please move towards the rear doors to leave the train. The next station is Liverpool Street. Change here for Central Line, Circle Line, Hammersmith & City Line and Metropolitan Line and Main Line Suburban rail services. Please mind the gap between the train and the platform. This train terminates at Redbridge.
Task 1
See MoreListening A2: Transport announcements – 1
Are the sentences true or false?
Task 2
See MoreListening A2: Transport announcements – 2
Match the numbers with the information.
Missing a class
Listen to a student explain why she can’t come to class to practise and improve your listening skills.
Do the preparation task first. Then listen to the audio and do the exercises.
Preparation
See MoreListening A2: Missing a class – preparation
Complete the phrases with the words.
Transcript
See MoreStudent: Excuse me, Ms Henderson?
Teacher: Yes, Diana. How can I help you?
Student: I’m sorry, but I can’t come to class next Wednesday. I have a doctor’s appointment.
Teacher: OK. Thanks for letting me know.
Student: Is there anything to do at home?
Teacher: Let me just check my notebook. OK, first of all … you need to read chapters 17, 19 and 20 in the book. There are also some articles and a video to watch – those are online. I’ll post the links online in the usual place.
Student: Chapters 17 to 20.
Teacher: Yes, except chapter 18. Chapters 17, 19 and 20.
Student: Ah, OK. Um … is there a deadline?
Teacher: Yes, this Friday. But there’s something else. I was going to give you all a practice test.
Student: A practice test?
Teacher: Yes, to help people prepare for the mid-term exam.
Student: Ah. All right.
Teacher: Don’t worry, I can send you the practice test by email on Wednesday. Can you send it to me before Friday?
Student: Sure, no problem.
Teacher: And don’t forget to bring a certificate from the doctor to the office.
Student: Thanks, Ms Henderson! I’ll do that.
Teacher: You’re welcome, Diana. Take care.
Task 1
See MoreTask 2
See MoreListening A2: Missing a class – 2
Put the words in order to make sentences.
The first English class
Listen to a teacher give students information about a new course to practise and improve your listening skills.
Do the preparation task first. Then listen to the audio and do the exercises.
Preparation
See MoreListening A1: The first English class – preparation
Put the words in the correct order.
Transcript
See MoreHello, everyone. Hello! It’s nice to see you all here. Welcome to British Life and Language. I am your teacher. My name is Lindsay Black. That’s L-I-N-D-S-A-Y Black. Before we begin, some information about the class.
Our class is in room 13, on the first floor. When you go upstairs, turn left to find the room. Again, that’s room 13.
We have class twice a week, on Monday and Wednesday. Our class begins at 4.30 p.m. and lasts 90 minutes, so we finish at 6 p.m. That’s 4.30 to 6. Please arrive on time, OK?
Also, I have an office hour if you have questions. I’m in office 7B on the second floor. My office hour is Friday at 6 p.m. So, if you have any questions or problems or want to talk to me, it’s Friday at 6 p.m. in office 7B.
We begin next week, on March the 13th. That’s Monday, March the 13th. The course ends on May the 20th. May the 20th is the last day.
I think that’s all … Oh, one more thing. For this course you need the book. Here it is: British Life and Language Level 1 Student’s Book. So, please get a copy of the book. I don’t want to see any photocopies of the book, thank you! Remember, it’s level 1 student’s book. Don’t buy the teacher’s book.
I think that’s all, everyone. I look forward to working with you. See you next Monday!
Task 1
See MoreListening A1: The first English class – 1
Are the sentences true or false?
Task 2
See MoreShopping for clothes
Listen to a conversation in a shop to practise and improve your listening skills.
Do the preparation task first. Then listen to the audio and do the exercises.
Preparation
See MoreListening A1: Shopping for clothes – preparation
Transcript
See MoreShop assistant: Hello, can I help you?
Customer: I’m just looking, thanks.
Customer: Excuse me?
Shop assistant: Yes?
Customer: Where are the changing rooms?
Shop assistant: They’re over there. Behind you.
Customer: Thank you.
Customer: Hi. Excuse me again. Do you have this jumper in black?
Shop assistant: Yes, just a moment. What size do you need?
Customer: Extra small, please.
Shop assistant: Here you are.
Customer: How much is this?
Shop assistant: It’s £29.
Customer: Can I pay by credit card?
Shop assistant: Yes, you can. Of course.
Shop assistant: Would you like a bag for that?
Customer: Yes, please.
Task 1
See MoreListening A1: Shopping for clothes – 1
Put the questions in the order that you hear them.
Task 2
See MoreListening A1: Shopping for clothes – 2
Match the answers with the questions.
Organising a group project
Listen to people organising a group project and answer the questions to practise and improve your listening skills.
Do the preparation task first. Then listen to the audio and do the exercises.
Preparation
See MoreListening A1: Organising a group project – preparation
Match the times with the words.
Transcript
See MoreCara: So for our group project, do you want to start this week?
Selim: Yeah, I want to start early so we have enough time.
Robert: Me too, but I’ve got a big maths project too.
Cara: How about we meet first to plan what we’re going to do? Just for an hour.
Robert: Good idea, Cara.
Cara: When are you free?
Robert: I can always do mornings before 10.
Cara: Robert … Uh …
Selim: I’m sleeping before 10!
Robert: OK! OK, so when are you two free?
Cara: Wednesdays are good for me. But not very early, please!
Selim: I can’t do the mornings on Wednesdays but I have 3 till 5 free.
Robert: I can do 4 o’clock, just before my maths class.
Cara: Great, 4 then. Where shall we meet?
Selim: The library?
Robert: I don’t know. The library isn’t a good place for a planning meeting as we can’t talk in there.
Cara: How about the university café? It’s near the library. We can talk in there. And eat cake.
Selim: Cake is good.
Robert: OK, so Wednesday at the café. I need to leave at ten to five to go to my maths class.
Cara: No problem. Planning will take less than an hour.
Selim: OK! See you Wednesday for cake.
Robert and Cara: See you, Selim!
Task 1
See MoreListening A1: Organising a group project – 1
Are the sentences true or false?
Task 2
See MoreListening A1: Organising a group project – 2
Match the phrases that mean the same thing.
testing
?
Ordering in a café
Listen to people ordering food and drinks in a café to practise and improve your listening skills.
Do the preparation task first. Then listen to the audio and do the exercises.
Preparation
See MoreListening A1: Ordering in a café – preparation
Put the words in the correct group.
Transcript
See MoreCustomer 1: Can I have an orange juice, please?
Server: Regular or large?
Customer 1: How big is a large?
Server: This is a large. This is a regular.
Customer 1: I’ll have a large, then, please. Without ice.
Server: OK, coming up.
Customer 1: Sorry, I wanted freshly squeezed orange juice.
Server: I’m afraid we only have bottled juices.
Customer 1: Oh, then I’ll have an apple juice instead, please.
Server: Here you go. That’s £3.50, please.
Customer: Thanks.
Server: Thank you.
Server: Can I help anyone?
Customer 2: Who’s next?
Customer 3: You were first, I think.
Customer 2: What teas do you have?
Server: Breakfast tea, mint and green tea.
Customer 2: A mint tea and a slice of lemon cake, please.
Server: To eat in or take away?
Customer 2: Take away, please.
Server: There you go. That’ll be £4.20, please.
Customer 2: Sorry, I’ve only got a fifty.
Server: That’s OK. Here’s your change … 5, 10, 30, 50.
Server: Who’s next?
Customer 4: Can I have a …
Customer 3: Sorry, I think I was in front of you.
Customer 4: Oh, sorry!
Customer 3: Can I have a chocolate chip cookie, please?
Server: Would you like a drink with that?
Customer 3: No, thanks. Just the cookie.
Server: OK, then. That’s 95p, please.
Customer 3: Thanks. I think that’s right.
Server: 50, 70, 80, 85, 90, 92, 94, yep, 95. Thank you.
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