Photo AI
The alkanes are a group of hydrocarbons that are commonly used as fuels - Leaving Cert Chemistry - Question 6 - 2010
Question 6
The alkanes are a group of hydrocarbons that are commonly used as fuels. The simplest of the alkanes is methane. Another alkane of molecular formula C₅H₁₂ has severa... show full transcript
Worked Solution & Example Answer:The alkanes are a group of hydrocarbons that are commonly used as fuels - Leaving Cert Chemistry - Question 6 - 2010
Step 1
What are (i) hydrocarbons, (ii) isomers?
Answer
(i) Hydrocarbons:
Hydrocarbons are organic compounds that consist only of carbon and hydrogen atoms. They are the foundational compounds of fossil fuels and can be found in various forms, such as gases, liquids, or solids.
(ii) Isomers:
Isomers are compounds that share the same molecular formula but differ in their structure and arrangement of atoms. This means they can have different physical and chemical properties.
Step 3
Mention two situations in which there may be a hazardous build-up of methane gas. Why are the levels of methane in the lower atmosphere a cause of environmental concern?
Answer
- In coal mines where methane can accumulate in confined spaces.
- In fuel tanks or tankers that may leak.
Why are the levels of methane in the lower atmosphere a cause of environmental concern?
Methane is a potent greenhouse gas that can contribute significantly to global warming, as it has a much higher heating potential than carbon dioxide over a shorter time frame.
Step 4
What do you understand by the octane number of a fuel?
Answer
The octane number of a fuel measures its ability to resist knocking or pinging during combustion, which occurs when fuel combusts prematurely in an engine. A higher octane number indicates better performance and efficiency in engines.
What is the significance of the compound 2,2,4-trimethylpentane in relation to octane numbers?
2,2,4-trimethylpentane is used as a reference standard when determining the octane number, often assigned an octane number of 100 due to its excellent resistance to knocking.
Step 5