4. Alkenes
(a) The table shows information about two alkenes - Edexcel - GCSE Chemistry - Question 4 - 2013 - Paper 1
Question 4
4. Alkenes
(a) The table shows information about two alkenes.
Complete the table to show the names and structures of these alkenes.
name
structure of a mo... show full transcript
Worked Solution & Example Answer:4. Alkenes
(a) The table shows information about two alkenes - Edexcel - GCSE Chemistry - Question 4 - 2013 - Paper 1
Step 1
Complete the table to show the names and structures of these alkenes.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The name of the alkene is ethene, which is represented structurally as:
H H
\ /
C=C
/ \
H H
This molecule contains a double bond between the two carbon atoms.
Step 2
State what is meant by unsaturated.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
An unsaturated compound is one that contains at least one double bond or triple bond between carbon atoms. This means it has the ability to react with additional atoms or molecules and can undergo addition reactions.
Step 3
Describe what is seen when ethene is passed into bromine water.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
When ethene is passed into bromine water, a color change occurs. The bromine water, which is originally orange, will become colorless as the bromine reacts with the ethene, indicating the formation of a dibrominated product.
Step 4
Explain what is meant by cracking.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Cracking refers to the process where large hydrocarbon molecules from crude oil are broken down into smaller, more useful products, such as alkenes and alkanes. This can involve thermal or catalytic methods to decompose larger chains.
Step 5
Complete the sentence by putting a cross ✗ in the box next to your answer.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The correct answer is D: polymerisation. This process involves the reaction of ethene molecules to form poly(ethene).
Step 6
Explain why the presence of waste plastic in landfill sites causes problems.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The presence of waste plastic in landfill sites causes environmental problems due to its non-biodegradable nature. Plastic bags like those made from polyethene can take hundreds of years to decompose, leading to accumulation in landfills and potential harm to wildlife and ecosystems.
