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Ethene can be prepared in the school laboratory using the arrangement of apparatus shown in Diagram 1 - Leaving Cert Chemistry - Question 2 - 2009
Question 2
Ethene can be prepared in the school laboratory using the arrangement of apparatus shown in Diagram 1. Ethylene can be prepared in the school laboratory using the ar... show full transcript
Worked Solution & Example Answer:Ethene can be prepared in the school laboratory using the arrangement of apparatus shown in Diagram 1 - Leaving Cert Chemistry - Question 2 - 2009
Step 1
Step 2
Write a balanced equation for the reaction involved in the preparation of ethene. What term describes this type of reaction?
Answer
The balanced equation for the preparation of ethene from calcium carbide is:
ightarrow ext{C}_2 ext{H}_4 + ext{Ca(OH)}_2$$ This type of reaction is referred to as a dehydration reaction.Step 3
State three procedures that should be observed when carrying out the preparation of ethene by this method.
Answer
- Keep the apparatus away from open flames, ensuring safety from fire hazards.
- Use proper protective goggles and wear gloves to avoid direct contact with chemicals.
- Ensure good ventilation and avoid inhaling glass wool, utilizing a mask if necessary.
Step 4
Give the name or formula of the solid Y used in the preparation of ethene in the school laboratory. Describe the appearance of this solid.
Answer
The solid Y used in the laboratory is sodium hydroxide, with the chemical formula NaOH. This solid typically appears as a white crystalline substance.
Step 5
Both ethene and ethyne are described as unsaturated. What does this mean? Describe a test you could carry out to show that ethyne can be tested and that it is unsaturated. What would you observe during the test?
Answer
Being unsaturated means that ethene and ethyne contain carbon-carbon double or triple bonds, respectively, allowing them to undergo addition reactions. To test ethyne's unsaturation, one could add bromine water (Br2) to the gas. The immediately observable effect would be the decolorization of the bromine, indicating the presence of the double bond and hence its unsaturation.
Step 6
Both ethene and ethyne can be burnt. What is the most noticeable difference seen when these combustions are carried out? Write a chemical equation for the complete combustion of either gas.
Answer
The most noticeable difference in the combustion reaction is that ethyne burns with a bright flame, producing more soot, while ethene burns more cleanly, yielding a blue flame. The complete combustion of ethene can be represented by the equation:
ightarrow 2 ext{CO}_2 + 2 ext{H}_2 ext{O}$$Step 7