Hydrocarbons (Alkanes and Alkenes) (2)

Question 1

What are hydrocarbons?

Answer 1

Compounds made entirely of hydrogen and carbon.

Question 2

What is the general formula for alkanes?

Answer 2

C_nH_(2n+2), where n is the number of carbon atoms.

Question 3

True or False: Alkanes are saturated hydrocarbons.

Answer 3

True

Question 4

What type of bond do alkanes contain?

Answer 4

Single covalent bonds.

Question 5

What is the simplest alkane?

Answer 5

Methane (CH4).

Question 6

Fill in the blank: The alkane with five carbon atoms is called ________.

Answer 6

Pentane.

Question 7

What is the state of alkanes with 1 to 4 carbon atoms at room temperature?

Answer 7

They are gases.

Question 8

What happens to the boiling point of alkanes as the number of carbon atoms increases?

Answer 8

The boiling point increases.

Question 9

Which alkane has the molecular formula C6H14?

Answer 9

Hexane.

Question 10

What is the main source of hydrocarbons?

Answer 10

Fossil fuels.

Question 11

True or False: Alkanes can undergo addition reactions.

Answer 11

False

Question 12

What is the process called when alkanes are broken down into smaller molecules?

Answer 12

Cracking.

Question 13

What is the primary use of alkanes in industry?

Answer 13

As fuels and lubricants.

Question 14

Fill in the blank: The alkane with seven carbon atoms is called ________.

Answer 14

Heptane.

Question 15

What type of isomerism can alkanes exhibit?

Answer 15

Structural isomerism.

Question 16

Which alkane has the molecular formula C8H18?

Answer 16

Octane.

Question 17

True or False: Alkanes are generally unreactive.

Answer 17

True

Question 18

What is the main environmental concern associated with burning hydrocarbons?

Answer 18

Production of carbon dioxide and other pollutants.

Question 19

Fill in the blank: The alkane with nine carbon atoms is called ________.

Answer 19

Nonane.

Question 20

What is the primary method of producing alkanes from crude oil?

Answer 20

Fractional distillation.

Question 21

True or False: Alkanes can form cyclic structures.

Answer 21

False

Question 22

What is the chemical formula for propane?

Answer 22

C3H8.

Question 23

What is the term for a hydrocarbon that contains at least one double or triple bond?

Answer 23

Unsaturated hydrocarbon.

Question 24

What is the boiling point trend observed in alkanes?

Answer 24

Boiling point increases with an increase in molecular weight (as you do down)

Question 25

What is the main characteristic of branched-chain alkanes compared to straight-chain alkanes?

Answer 25

They have lower boiling points.

Question 26

Fill in the blank: The alkane with ten carbon atoms is called ________.

Answer 26

Decane.

Question 27

What is the primary reaction type of alkanes?

Answer 27

Combustion.

Question 28

True or False: Alkanes can participate in substitution reactions.

Answer 28

True

Question 29

What is the formula for butane?

Answer 29

C4H10.

Question 30

Fill in the blank: The alkane with twelve carbon atoms is called ________.

Answer 30

Dodecane.

Question 31

What property of alkanes increases as the carbon chain length decreases?

Answer 31

Flammability

Question 32

True or False: Shorter alkanes are generally more volatile than longer alkanes.

Answer 32

True

Question 33

Fill in the blank: The boiling point of alkanes _______ with increasing molecular weight.

Answer 33

increases

Question 34

Which of the following alkanes is the most volatile? A) Pentane B) Butane C) Hexane

Answer 34

B) Butane

Question 35

What is the general trend in flammability as the number of carbon atoms in alkanes increases?

Answer 35

Flammability decreases

Question 36

What is a combustion reaction?

Answer 36

A combustion reaction is a chemical reaction that occurs when a substance combines with oxygen, producing heat and light.

Question 37

True or False: Combustion reactions always produce carbon dioxide and water.

Answer 37

True

Question 38

Fill in the blank: In a combustion reaction, fuel reacts with __________.

Answer 38

oxygen

Question 39

Which of the following is a common fuel used in combustion reactions? (A) Water (B) Methane (C) Salt

Answer 39

B) Methane

Question 40

What are the two main types of combustion reactions?

Answer 40

Complete combustion and incomplete combustion.

Question 41

What is the process of breaking down larger hydrocarbons into smaller ones called?

Answer 41

Cracking

Question 42

True or False: Cracking can only produce alkenes.

Answer 42

False

Question 43

What are alkenes?

Answer 43

Unsaturated hydrocarbons containing at least one carbon-carbon double bond.

Question 44

Fill in the blank: The primary source of hydrocarbons for cracking is __________.

Answer 44

Crude oil

Question 45

What is the main purpose of cracking crude oil?

Answer 45

To produce more valuable products such as gasoline (more volatile and flammable) and alkenes.

Question 46

List two types of cracking.

Answer 46

Steam cracking and catalytic cracking.

Question 47

What catalyst is commonly used in catalytic cracking?

Answer 47

Powdered Aluminium Oxide

Question 48

Multiple Choice: Which of the following is a product of cracking? A) Methane B) Ethylene C) Octane

Answer 48

B) Ethylene

Question 49

True or False: Alkenes are more reactive than alkanes.

Answer 49

True

Question 50

What is the general formula for alkenes?

Answer 50

CnH2n

Question 51

What type of reaction can alkenes undergo to form alcohols?

Answer 51

Hydration reaction (addition with water)

Question 52

Fill in the blank: The process of adding hydrogen to an alkene to form an alkane is called __________.

Answer 52

Hydrogenation

Question 53

What is the main environmental concern associated with cracking?

Answer 53

Production of greenhouse gases.

Question 54

Short answer: Name one use of alkenes in the industry.

Answer 54

Production of plastics (polymers)

Question 55

Multiple Choice: Which alkene is used as a starting material for the production of polyethylene? A) Propene B) Butene C) Ethene

Answer 55

C) Ethene

Question 56

True or False: Cracking occurs at high temperatures.

Answer 56

True

Question 57

What is the difference between steam cracking and catalytic cracking?

Answer 57

Steam cracking uses high heat and pressure, while catalytic cracking uses a catalyst to lower the temperature.

Question 58

Fill in the blank: The process of breaking down larger hydrocarbons can also produce __________, which are useful as fuels.

Answer 58

Smaller alkanes

Question 59

What is a common temperature range for steam cracking?

Answer 59

450 to 750 degrees Celsius

Question 60

Short answer: What is one advantage of catalytic cracking over steam cracking?

Answer 60

It produces higher yields of alkenes and lower temperatures.

Question 61

Multiple Choice: Which of the following alkenes is known for its use in the production of antifreeze? A) Ethylene B) Propylene C) Butylene

Answer 61

A) Ethylene

Question 62

True or False: Alkenes can participate in addition reactions.

Answer 62

True

Question 63

What is the process called when an alkene reacts with bromine?

Answer 63

Halogenation

Question 64

Fill in the blank: The simplest alkene is __________.

Answer 64

Ethene

Question 65

What type of bond is present in an alkene?

Answer 65

Double bond

Question 66

Multiple Choice: Which of the following compounds is an alkene? A) C2H6 B) C3H8 C) C4H8

Answer 66

C) C4H8

Question 67

Short answer: How does the presence of a double bond in alkenes affect their reactivity?

Answer 67

It increases their reactivity compared to alkanes.

Question 68

What is the primary advantage of using alkenes in chemical synthesis?

Answer 68

Their ability to undergo a variety of reactions due to the double bond.

Question 69

True or False: Cracking can only be done in refineries.

Answer 69

False

Question 70

Short answer: What is the significance of cracking in the petroleum industry?

Answer 70

It helps meet the demand for fuels and chemicals.

Question 71

Equation for cracking

Answer 71

long chain alkane --> Shorter alkane + Alkene e.g Decane --> Heptane + Propene

Question 72

What is the test for Alkenes and its result

Answer 72

Bromine water orange --> colourless