Hydrocarbon Examples in Chemistry

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Hydrocarbon.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Chemistry.

Concept Recap

A hydrocarbon is an organic compound made only of carbon and hydrogen atoms. Common hydrocarbon families include alkanes, alkenes, and alkynes.

Hydrocarbons are the simplest organic molecules: just carbon plus hydrogen.

Read the full concept explanation →

How to Use These Examples

Read the first worked example with the solution open so the structure is clear.
Try the practice problems before revealing each solution.
Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: Hydrocarbon starts by identifying the carbon skeleton, functional group, and repeating pattern if present.

Common stuck point: Students often know a formula related to hydrocarbon but skip the recognition step: Am I using carbon structure, bonds, functional groups, or repeating units to explain the molecule? That leads to a correct-looking substitution attached to the wrong chemical model.

Sense of Study hint: Ask: Am I using carbon structure, bonds, functional groups, or repeating units to explain the molecule?

Worked Examples

Example 1

medium

Write the balanced complete combustion equation for ethane (

C_2H_6

Answer

2C_2H_6 + 7O_2 \rightarrow 4CO_2 + 6H_2O

First step

Each

C_2H_6

gives

2CO_2

and

3H_2O

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Example 2

medium

Why does combustion of any hydrocarbon always produce only

CO_2

and

H_2O

when complete?

Example 3

hard

Hex-1-yne (

C_6H_{10}

) reacts with excess

H_2

over a catalyst. What product forms and what is its family?

Example 4

hard

Why does crude oil distillation work to separate hydrocarbons?

Example 5

challenge

22.4\text{ L}

of an unknown gaseous hydrocarbon at STP weighs

30\text{ g}

. Identify it.

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

easy

A hydrocarbon is made of only which two elements?

Example 2

easy

What is the general formula for an alkane?

Example 3

easy

How many hydrogens does the alkane with 3 carbons (propane) have?

Example 4

easy

Which hydrocarbon family contains a carbon-carbon double bond?

Example 5

easy

What is the general formula for an alkene?

Example 6

easy

Ethyne (acetylene) has a carbon-carbon triple bond. What family is it in?

Example 7

easy

C_2H_6

saturated or unsaturated?

Example 8

easy

Are all carbon-containing molecules hydrocarbons?

Example 9

medium

Determine the molecular formula of the alkene with 4 carbons (butene).

Example 10

medium

Compare the hydrogen counts of the 5-carbon alkane, alkene, and alkyne.

Example 11

medium

A hydrocarbon has formula

C_4H_{10}

. Which family is it, and is it saturated?

Example 12

medium

Why does complete combustion of any hydrocarbon always give

CO_2

and

H_2O

Example 13

medium

A 3-carbon hydrocarbon has 4 hydrogens. Identify its family.

Example 14

medium

A student claims

CH_3OH

is a hydrocarbon because it has carbon and hydrogen. Correct this.

Example 15

medium

Which has more hydrogens: a 6-carbon alkane or a 6-carbon alkene? By how many?

Example 16

medium

Determine the molecular formula of the alkyne with 4 carbons (butyne).

Example 17

medium

Why are alkanes generally less reactive than alkenes?

Example 18

challenge

A saturated hydrocarbon contains 7 carbons. Write its formula and its complete combustion equation.

Example 19

challenge

An unsaturated hydrocarbon has formula

C_5H_8

. State its family and how many degrees of unsaturation it has relative to the alkane.

Example 20

challenge

Burning 1 mol of butane gives how many moles of water? (

2C_4H_{10} + 13O_2 \rightarrow 8CO_2 + 10H_2O

)

Example 21

easy

Is methane (

CH_4

) a hydrocarbon?

Example 22

easy

Is ethanoic acid (

CH_3COOH

) a hydrocarbon?

Example 23

easy

How many hydrogens does ethane (

n=2

, alkane) have?

Example 24

easy

Determine the formula of the alkene with

3

carbons (propene).

Example 25

easy

Ethene (

C_2H_4

) belongs to which hydrocarbon family?

Example 26

easy

Is benzene (

C_6H_6

) classified as a hydrocarbon?

Example 27

medium

Compare the hydrogen counts of the 6-carbon alkane, alkene, and alkyne.

Example 28

medium

A hydrocarbon has formula

C_5H_{12}

. Identify its family and saturation state.

Example 29

medium

Determine the molecular formula of the alkyne with

5

carbons (pentyne).

Example 30

medium

A hydrocarbon with

4

carbons has

6

hydrogens. Identify its family.

Example 31

medium

A student says ethanol (

CH_3CH_2OH

) is a hydrocarbon. Is this correct?

Example 32

medium

Compare

C_3H_8

and

C_3H_6

. Which is the alkene and how do their hydrogen counts compare?

Example 33

medium

Why are alkenes more reactive than alkanes toward bromine water?

Example 34

medium

What is the molecular formula of the alkane with

10

carbons (decane)?

Example 35

medium

An unsaturated hydrocarbon decolorizes bromine water. Is it likely an alkane, alkene, or alkyne?

Example 36

hard

Write the balanced complete combustion equation for octane (

C_8H_{18}

Example 37

hard

Burning

1\text{ mol}

propane (

C_3H_8 + 5O_2 \rightarrow 3CO_2 + 4H_2O

) produces how many moles of

H_2O

Example 38

hard

A hydrocarbon has

90\%

carbon by mass. Calculate its empirical formula. (

C=12

H=1

)

Example 39

hard

1\text{ mol}

of an unknown hydrocarbon

C_xH_y

produces

3\text{ mol}

CO_2

and

3\text{ mol}

H_2O

on complete combustion. Identify it.

Example 40

hard

Predict the products of catalytic cracking of decane (

C_{10}H_{22}

) producing one alkane and one alkene, both with

5

carbons.

Example 41

hard

Cyclohexane has formula

C_6H_{12}

, the same as hex-1-ene. Why doesn't the formula match the alkane formula?

Example 42

challenge

4.4\text{ g}

sample of a hydrocarbon burns to give

13.2\text{ g}

CO_2

and

7.2\text{ g}

H_2O

. Find its empirical formula. (

M(CO_2)=44

M(H_2O)=18

)

← Back to Hydrocarbon Practice Mode

Related Concepts

Organic Chemistry Polymer

Background Knowledge

These ideas may be useful before you work through the harder examples.

organic chemistry