Organic formulae and functional groups

விளையாடிக் கற்றுக்கொள்ளுங்கள்

ஆற்றல் சம்பாதிக்க இந்த கேள்விகளுக்குப் பதிலளியுங்கள், பின்னர் மீன் பிடித்து ஆராயுங்கள். கணக்கு தேவையில்லை.

கல்வியாளர்களுக்கு: Organic formulae and functional groups (MYP Chemistry, Year 4)-க்கான தயாரான பாட ஸ்லைடுகள், திருப்புதல் குறிப்புகள் — உங்கள் பாடத்தில் அவற்றைப் பயன்படுத்தவும், அல்லது கற்பவர்கள் நேரலை விளையாட்டாக விளையாடும் ஊடாடும் வகுப்பு செயல்பாடாக தலைப்பை இயக்கவும்.

பாட குறிப்புகள்

Big idea: organic formulae and functional groups

  • Key concept: Relationships. A functional group is the atom or group of atoms responsible for characteristic reactions. Homologous-series members share a functional group and show a pattern in their formulae.
  • Related concepts: Models and evidence. Use a scientific explanation to make predictions, then test it against observations.
  • Global context: Scientific and technical innovation. Functional groups guide the design and identification of useful organic compounds.

Organic Formulae

  • Organic compounds contain carbon (except metal carbonates, CO₂, CO).
  • Hydrocarbons contain only hydrogen and carbon atoms.
  • Displayed formula shows the spatial arrangement of all atoms and bonds.
  • Structural formula shows only important bonds (e.g., C=C); identical groups may be bracketed.
  • Molecular formula gives the actual number of each atom in a compound.
  • Structural isomers have the same molecular formula but different structural formulae (e.g., C₄H₁₀: butane and 2-methylpropane).

Structural isomers of C4H10

Structural isomers of C4H10

Homologous Series

  • A homologous series is a family of organic compounds with the same functional group and similar chemical properties.
  • The functional group is a specific arrangement of atoms responsible for characteristic reactions.
  • Key functional groups: alkane (C–C), alkene (C=C), alcohol (–OH), carboxylic acid (–COOH), ester (–COO–).
  • General formulae: alkane CₙH₂ₙ₊₂, alkene CₙH₂ₙ, alcohol CₙH₂ₙ₊₁OH, carboxylic acid CₙH₂ₙ₊₁COOH.
  • Members differ by CH₂ and show a gradation in physical properties (e.g., boiling point increases with chain length).
  • Example: ethanol (C₂H₅OH, b.p. 78°C) and propanol (C₃H₇OH, b.p. 97°C) are both alcohols with –OH group.

Displayed formulae of ethane, ethene, ethanol and ethanoic acid

Displayed formulae of ethane, ethene, ethanol and ethanoic acid

Saturated & Unsaturated Compounds

  • Saturated compounds have only single C–C bonds (e.g., alkanes).
  • General formula for alkanes: CₙH₂ₙ₊₂; first three: methane (CH₄), ethane (C₂H₆), propane (C₃H₈).
  • Unsaturated compounds contain at least one C=C double bond (e.g., alkenes).
  • General formula for alkenes: CₙH₂ₙ; first three: ethene (C₂H₄), propene (C₃H₆), butene (C₄H₈).
  • Mnemonic: Saturated = Single bonds; Unsaturated = doUble bonds.

Naming Organic Compounds

  • Name consists of a stem (number of C atoms) and suffix (functional group).
  • Stems: 1=meth, 2=eth, 3=prop, 4=but, 5=pent, 6=hex.
  • Suffixes: -ane (alkane), -ene (alkene), -anol (alcohol), -anoic acid (carboxylic acid), -yl-anoate (ester).
  • For positional isomers, number the carbon chain to locate the functional group (e.g., propan-1-ol, but-2-ene).
  • For a simple monocarboxylic acid, number the chain from the carboxyl carbon, which is carbon 1.
  • Ester names: the alcohol part (alkyl) comes first, then the carboxylic acid part (alkanoate) – e.g., methyl ethanoate from methanol + ethanoic acid.

Key Functional Groups Table

  • Alkane: C–C, suffix -ane.
  • Alkene: C=C, suffix -ene.
  • Alcohol: –OH, suffix -anol.
  • Carboxylic acid: –COOH, suffix -anoic acid.
  • Ester: –COO–, suffix -yl-anoate.

Think like a scientist

  • Classify a teacher-provided set of organic structures by functional group and compare their reaction patterns.
  • Comparison: the functional group in each structure. Outcome: the assigned organic family and expected reaction type.
  • Control: compare structures using the same naming rules. Explain why this makes the comparison fairer.
  • Evidence: Use a consistent method, repeated observations where appropriate and a table with labelled quantities and units. Keep unexpected results and investigate their cause.
  • Safety: Practical activities need teacher supervision and an appropriate risk assessment. Use the provided data or simulation where the investigation specifies it.
  • Inquiry task: State a testable question, predict the outcome using the science, then explain how your observations would support or challenge the prediction.

Evaluate the science

  • Functional groups guide the design and identification of useful organic compounds.
  • A molecular formula can describe more than one structure, so it may not uniquely identify a compound.
  • Evaluation task: Link your conclusion to evidence, identify a limitation and suggest a specific improvement. Distinguish a measured result from an explanation of its cause.

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பதிவு செய்க — இலவசம்உள்நுழைக

பயிற்சி கேள்விகள்

இலவச முன்னோட்டம் — 52-இல் 8 கேள்விகள். அனைத்தையும் பார்க்க பதிவு செய்யவும்.

  1. 1.Which of the following formulae shows an alkane?

    Easy
    • AC2H4
    • BC4H8
    • CC4H10
    • DC5H10

  2. 2.Which of the following is not a feature of a homologous series?

    Easy
    • ACompounds have the same functional group
    • BCompounds have the same physical properties
    • CCompounds have the same general formula
    • DCompounds have similar chemical properties

  3. 3.What is the general formula of the alkenes?

    Easy
    • ACnH2n+2
    • BCnH2n
    • CCnH2n-2
    • DCnH2n+1OH

  4. 4.What is the name of the compound with the formula CH3CH2CH2OH?

    Easy
    • APropan-1-ol
    • BPropan-2-ol
    • CButan-1-ol
    • DButan-2-ol

  5. 5.Which of the following structures shows a compound that belongs to a different homologous series to octane?

    Medium
    • AA straight-chain hydrocarbon with all single bonds and 8 carbons
    • BA hydrocarbon with 8 carbons and one double bond
    • CA hydrocarbon with 8 carbons and all single bonds
    • DA hydrocarbon with 8 carbons and only single bonds

  6. 6.Which of the following compounds is unsaturated?

    Easy
    • AC2H6
    • BC3H8
    • CC2H4
    • DCH4

  7. 7.What is the name of the compound with the structural formula CH3CH2CH2COOH?

    Easy
    • AButanoic acid
    • BPropanoic acid
    • CButanol
    • DButanone

  8. 8.Three statements about propane and propanol are listed below. 1. Propane and propanol belong to the same homologous series. 2. Propanol is a compound that contains three carbon atoms. 3. Propane is an unsaturated hydrocarbon. Which statements are correct?

    Medium
    • A1 and 2 only
    • B1 and 3 only
    • C2 only
    • D3 only

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இந்த தலைப்பிற்கான ஒவ்வொரு கேள்வியையும், ஸ்லைடுகளையும், ஃப்ளாஷ் கார்டுகளையும் மற்றும் திருப்புதல் குறிப்புகளையும் பார்க்க இலவச கணக்கை உருவாக்கவும்.

பதிவு செய்க — இலவசம்உள்நுழைக

முந்தைய தேர்வுகள்

இந்த தலைப்பிற்கான முந்தைய தேர்வு பயிற்சி விரைவில் வருகிறது.
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