Introductory Organic Chemistry (Edexcel International A Level (IAL) Chemistry): Flashcards
Exam code: YCH11
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What is a hazard in a chemistry context?
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What is a hazard in a chemistry context?
A hazard is an inherent property of a chemical substance that has the potential to cause harm.
What is a risk in a chemistry context?
A risk is the chance that a hazard will actually cause harm, depending on how the substance is used.
How does wearing eye protection affect the hazard and risk of using hydrochloric acid?
Wearing eye protection does not change the hazard of hydrochloric acid. It reduces the risk of the acid causing harm to your eyes.
True or False?
The hazard of a substance changes depending on how you use it.
False.
The hazard relates to the inherent properties of the substance and does not change with use. It is the risk that changes depending on how the substance is used.
What does the corrosive hazard symbol warn about?
The corrosive symbol warns that the substance can cause skin burns and permanent eye damage.
A substance labelled as having acute toxicity can cause .......... effects, even in small quantities.
A substance labelled as having acute toxicity can cause life-threatening effects, even in small quantities.
What is the purpose of a risk assessment in a laboratory?
A risk assessment identifies the hazards of substances being used, evaluates the risks associated with how they will be used, and sets out control measures to reduce those risks.
Give two factors a risk assessment might consider when deciding on control measures for a practical.
A risk assessment might consider:
Whether the substance will be heated
Whether ventilation or a fume cupboard is needed
True or False?
In an exam question about precautions, stating 'wear a lab coat and goggles' is always a sufficient answer.
False.
Wearing a lab coat and goggles is standard practice in any laboratory. A valid precaution must refer to the specific procedure, for example stating that a step producing HCl gas must be carried out in a fume cupboard.
Define homologous series
A homologous series is a group of organic compounds that share the same functional group, where each successive member differs by CH2.
Define functional group
A functional group is an atom or group of atoms within a molecule that determines the chemical and physical properties of that compound.
What four features do all members of a homologous series share?
All members of a homologous series:
Have the same functional group
Have the same general formula
Have similar chemical properties
Differ by CH2 between successive members
True or False?
Members of a homologous series have identical physical properties.
False.
Members of a homologous series have gradually changing physical properties, such as boiling point, melting point and density, as the size of the molecule increases up the series.
Ethanol and propanol belong to the same .......... because they share the same functional group and differ by one CH2 unit.
Ethanol and propanol belong to the same homologous series because they share the same functional group and differ by one CH2 unit.
Why do members higher in a homologous series tend to have higher boiling points?
As molecules increase in size up the series, there are more electrons and greater London dispersion forces between molecules. More energy is required to overcome these forces, so the boiling point increases.
What does the symbol R represent in the structural formula of a functional group?
R represents any other atom or group of atoms attached to the functional group, except for hydrogen.
True or False?
All members of a homologous series have similar chemical properties.
True.
Because all members share the same functional group, they undergo similar chemical reactions and therefore have similar chemical properties.
What does the stem 'but-' indicate in an organic compound name?
The stem but- indicates that the longest carbon chain in the molecule contains 4 carbon atoms.
What is an alkyl group?
An alkyl group is a hydrocarbon side-chain derived from an alkane, formed by removing one hydrogen atom and named by adding '-yl' to the alkane stem (e.g. methyl, ethyl).
When numbering carbon atoms in a chain to name a compound, always start from the end that gives the .......... numbers in the name.
When numbering carbon atoms in a chain to name a compound, always start from the end that gives the lowest possible numbers in the name.
How is the prefix 'di-' used in IUPAC nomenclature?
The prefix di- is added in front of a substituent name to indicate that two identical alkyl groups or functional groups are present. Numbers indicating their positions are separated by a comma.
Define addition reaction
An addition reaction is an organic reaction in which two or more molecules combine to give a single product with no other products formed.
Define elimination reaction
An elimination reaction is a reaction in which a small molecule (such as H2O or HCl) is removed from an organic molecule.
True or False?
In a condensation reaction, two organic molecules join together with no other products formed.
False.
In a condensation reaction, two organic molecules join together but a small molecule such as H2O or HCl is also eliminated as a product.
In organic chemistry, what does the symbol [O] represent in a redox equation?
The symbol [O] represents one atom of oxygen from an oxidising agent. It is used to simplify equations for organic oxidation reactions without writing out the full oxidising agent.
What structural requirement must a monomer have to undergo addition polymerisation?
A monomer must contain at least one C=C double bond to undergo addition polymerisation. The double bond opens to allow monomers to link into a long-chain polymer.
True or False?
If an alkyl side-chain appears twice in a molecule, it is listed twice in alphabetical order.
False.
When the same alkyl group appears more than once, a multiplying prefix (di-, tri-, tetra-) is placed before its name. The group is only listed once in the name.
Define structural isomers
Structural isomers are compounds that have the same molecular formula but different structural formulae.
What is chain isomerism?
Chain isomerism is a type of structural isomerism where compounds have the same molecular formula but different lengths of longest carbon chain, caused by branching.
What is positional isomerism?
Positional isomerism is a type of structural isomerism where compounds have the same molecular formula and functional group, but the functional group is located on different carbon atoms.
True or False?
Propene and cyclopropane are structural isomers.
True.
Both propene and cyclopropane have the molecular formula C3H6 but differ in their structural formulae, making them structural isomers.
Pentane and 2,2-dimethylpropane are examples of .......... isomers because they have the same molecular formula but different lengths of longest carbon chain.
Pentane and 2,2-dimethylpropane are examples of chain isomers because they have the same molecular formula but different lengths of longest carbon chain.
What is the difference between butan-1-ol and butan-2-ol, and what type of isomerism does this represent?
Both butan-1-ol and butan-2-ol have the molecular formula C4H10O. They differ in the position of the hydroxyl group: it is on the first carbon in butan-1-ol and on the second carbon in butan-2-ol. This is positional isomerism.
How does chain isomerism arise in organic molecules?
Chain isomerism arises through branching in the carbon skeleton. The same atoms are present but arranged so that the longest continuous carbon chain differs between isomers.
True or False?
Structural isomers always have different molecular formulae.
False.
Structural isomers have the same molecular formula but different structural formulae. It is the arrangement of atoms that differs, not the overall composition.
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