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Alkanes

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Question 8

The alkanes are a homologous series of hydrocarbons. The alkenes are another homologous series of hydrocarbons containing at least one carbon-carbon double bond.

The tables below show the names and molecular formulas of three members of each series:

Table 1: Alkanes

Name of alkaneMolecular formula
methaneCH4\text{CH}_4CH4​
ethaneC2H6\text{C}_2\text{H}_6C2​H6​
propaneC3H8\text{C}_3\text{H}_8C3​H8​

Table 2: Alkenes

Name of alkeneMolecular formula
propeneC3H6\text{C}_3\text{H}_6C3​H6​
buteneC4H8\text{C}_4\text{H}_8C4​H8​
penteneC5H10\text{C}_5\text{H}_{10}C5​H10​

Questions

a.

What is the general formula for the homologous series of alkanes?

  • A: CnH2n−2\text{C}_n\text{H}_{2n-2}Cn​H2n−2​
  • B: CnH2n\text{C}_n\text{H}_{2n}Cn​H2n​
  • C: CnH2n+1\text{C}_n\text{H}_{2n+1}Cn​H2n+1​
  • D: CnH2n+2\text{C}_n\text{H}_{2n+2}Cn​H2n+2​
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b.

What is the general formula for the homologous series of alkenes? Use the information from Table 2 to help you answer.

  • A: CnH2n\text{C}_n\text{H}_{2n}Cn​H2n​
  • B: CnH2n−2\text{C}_n\text{H}_{2n-2}Cn​H2n−2​
  • C: CnH2n+2\text{C}_n\text{H}_{2n+2}Cn​H2n+2​
  • D: CnH2n+1\text{C}_n\text{H}_{2n+1}Cn​H2n+1​
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c.

State two other features of a homologous series of compounds.

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d.

Alkanes are saturated hydrocarbons and alkenes are unsaturated hydrocarbons. State what is meant by the term saturated.

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e.

Draw the displayed formula for butane, C4H10\text{C}_4\text{H}_{10}C4​H10​.

[1]
f.

Draw the displayed formula for but-2-ene, C4H8\text{C}_4\text{H}_8C4​H8​.

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g.

The reaction between propane, C3H8\text{C}_3\text{H}_8C3​H8​, and chlorine, Cl2\text{Cl}_2Cl2​, is a substitution reaction. One product of this reaction is hydrogen chloride, HCl\text{HCl}HCl. State the condition required for this reaction to occur.

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h.

Complete the following displayed template to show the other organic product (1-chloropropane, C3H7Cl\text{C}_3\text{H}_7\text{Cl}C3​H7​Cl) of this reaction by adding the missing bonds and atoms:

HH∣∣H−C−C−C∣∣HH\begin{array}{ccccccccc} & & \text{H} & & \text{H} & & & & \\ & & | & & | & & & & \\ \text{H} & - & \text{C} & - & \text{C} & - & \text{C} & & \\ & & | & & | & & & & \\ & & \text{H} & & \text{H} & & & & \end{array}H​−​H∣C∣H​−​H∣C∣H​−​C​​​
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Alkanes Questions

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