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Alkanes
Fichas del conjunto (38)
- 1What is the general formula for alkanes?CₙH₂ₙ₊₂
- 2Are alkanes saturated or unsaturated compounds?Saturated
- 3Describe the structure of cycloalkanesCycloalkanes have a ring of carbon atoms with two hydrogens attached to each carbon
- 4What is the general formula for cycloalkanes?CₙH₂ₙ
- 5TRUE OR FALSE: Cycloalkanes are saturated compoundsTRUE
Cycloalkanes contain only single C-C bonds but they are still considered saturated - 6Name this compound:3,4-diethylheptane
- 7Name this compound:4-ethyl-5-propyloctane
- 8Name this compound:3,4-dimethyl-4,5-diethyl-5-propyloctane
- 9What is the shape of an alkane molecule?Tetrahedral
- 10What is the bond angle around each carbon?109.5°
- 11In alkanes, what type of bond exists between carbon atoms, and between carbon and hydrogen atoms?Sigma (σ-) bond
- 12How are σ-bonds formed?Atomic orbitals on carbon and hydrogen atoms are positioned so that they overlap to form a new, shared orbital lying directly between the bonded atoms.
- 13σ-bonds are the strongest type of covalent bond. What makes them so strong?The high electron density between the nuclei means there is a strong electrostatic attraction between the nuclei and the shared pair of electrons. This means that σ-bonds have a high bond enthalpy.
- 14TRUE OR FALSE: Bonded atoms are free to rotate around the σ-bondTRUE
Whichever way the atoms point, the atomic orbitals between them will overlap - 15TRUE OR FALSE: Alkanes are very reactiveFALSE
They are UNreactive - 16What types of reactions do alkanes undergo?Combustion with oxygen
Substitution reactions with highly reactive free radical species - 17Why do alkanes have a low reactivity?The C-C and C-H σ-bonds all have a large bond enthalpy, making them very strong and difficult to break
The bonds are non-polar - they won't attract any positively or negatively charged particles - 18What does the boiling point of an alkane depend on?Size
Shape - 19How does the size of an alkane affect the boiling point?The longer the carbon chain, the more London forces there are.
Longer carbon chains have a larger molecular surface area so there is more surface contact between the molecules and there are more electrons to interact - 20How does the shape of an alkane affect boiling point?A branched alkane has a lower boiling point than its straight-chain isomer.
Branched-chain alkanes can't pack closely together and they have smaller molecular surface areas - so the London forces are reduced - 21What are the two types of combustion?Complete
Incomplete - 22What are the products of complete combustion?Carbon dioxide
Water - 23Give the balanced symbol equation for the complete combustion of propaneC₃H₈ + 5O₂ --> 3CO₂ + 4H₂O
- 24TRUE OR FALSE: Complete combustion reactions can happen with liquid alkanesFALSE
Complete combustion reactions happen between GASES, so liquid alkanes have to be vaporised first - 25TRUE OR FALSE Smaller alkanes turn into gases more easilyTRUE
- 26What is the term used to describe a substance's ability to turn into a gas?Volatility
- 27Complete the sentence: Smaller alkanes are _______ volatile, so they'll burn ______ easily tooSmaller alkanes are MORE volatile, so they'll burn MORE easily too.
- 28Alkanes make excellent fuels. Why?When alkanes burn, some energy is used to break the covalent bonds but more energy is released by forming the new products.
- 29Do larger alkanes or smaller alkalkanes release more energy per mole?Larger alkanes (more CO₂ and H₂O are formed)
- 30Alkanes make excellent fuels. What is the use of propane?Central heating
Cooking fuel - 31Alkanes make excellent fuels. What is the use of butane?Bottled and sold as camping gas
- 32What are petrol and diesel made up of?A mixture of alkanes and additives
- 33What are the products of incomplete combustion?Carbon monoxide
Water - 34Give the balanced symbol equation for the incomplete combustion of methane2CH₄ + 3O₂ --> 2CO + 4H₂O
- 35Why would breathing in carbon monoxide be dangerous?Carbon monoxide is better at binding to haemoglobin than oxygen is. This means that less oxygen will reach your cells
- 36What are the symptoms associated with carbon monoxide poisoning?Fatigue
Headaches
Nausea - 37Name 3 appliances that produce carbon monoxideGas- or oil-fired boilers and heaters
Gas stoves
Cool or wood fires
Cars
(Any appliance that burns alkanes can produce CO) - 38What could be done to prevent carbon monoxide poisoning?All appliances that use an alkane-based fuel need to be properly ventilated, checked and maintained regularly
Carbon moonoxide detectors should be used
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- El usuario ha eliminado su información de asignaturas Fichas sobre Alkanes, creado por Usuario eliminado el 12/03/2018.
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- Creado por Yinka F · 6 mar 2018
- Copiado por Yinka F · 12 mar 2018
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