Chemistry /Chemistry - Organic Families 1 Flashcards Part 2
What is the molecular formula and the IUPAC name for the 1st member of the alkenes?
C2H4
Ethene
Tap to flip
Space↑↓
←→Navigate
SSpeak
FFocus
1/25
Key Terms
Term
Definition
What is the molecular formula and the IUPAC name for the 1st member of the alkenes?
C2H4
Ethene
You have to number the carbon chain in such a way that the ….
Double bond is coming from the lowest carbon possible and name the main chain based on its number of carbons
Hover to peek or log in to view all
How many isomers of the third member of the alkene series?
3
Explain how sigma and pi bonding take place between carbon atoms in alkene molecules.
Alkenes are unsaturated compounds, contain a double bond between two of the carbon atoms.
Double bonds are formed by a sigma bond and a pi bond
Hover to peek or log in to view all
Name the physical properties of ethene.
Ethene is a colourless gas with a sweet smell.
It is insoluble in water but dissolved in non-polar substances eg cytohexane
Hover to peek or log in to view all
Account for the greater reactivity of alkenes compared to alkanes.
Alkenes are unsaturated.
This double bond has a high electron density and includes a pi bond which is weaker and easily broken
Related Flashcard Decks
Study Tips
- Press F to enter focus mode for distraction-free studying
- Review cards regularly to improve retention
- Try to recall the answer before flipping the card
- Share this deck with friends to study together
| Term | Definition |
|---|---|
What is the molecular formula and the IUPAC name for the 1st member of the alkenes? | C2H4
Ethene |
You have to number the carbon chain in such a way that the …. | Double bond is coming from the lowest carbon possible and name the main chain based on its number of carbons |
How many isomers of the third member of the alkene series? | 3 |
Explain how sigma and pi bonding take place between carbon atoms in alkene molecules. | Alkenes are unsaturated compounds, contain a double bond between two of the carbon atoms.
Double bonds are formed by a sigma bond and a pi bond |
Name the physical properties of ethene. | Ethene is a colourless gas with a sweet smell.
It is insoluble in water but dissolved in non-polar substances eg cytohexane |
Account for the greater reactivity of alkenes compared to alkanes. | Alkenes are unsaturated.
This double bond has a high electron density and includes a pi bond which is weaker and easily broken |
You have to number the carbon chain in such a way that the …. | Double bond is coming from the lowest carbon possible and name the main chain based on its number of carbons |
Give two industrial applications of alkenes. | 1 ethene is used to speed up the ripening of fruit
2 polyethene is used in plastic production |
Give the word equation for the experiment of preparing ethene. | Ethanol —-(aluminium oxide—-> ethene + water |
Give the chemical equation for preparing ethene. | C2H5OH —(Al2O3) —> C2H4 + H2O |
Describe the procedure to prepare ethene. | Glass wool soaked in ethanol
Aluminium oxide gently heated allowing the ethanol to vaporise and pass over the Aluminium Oxide (dehydrating agent).
Ethanol is dehydrated to ethene + water
Ethene is carried by delivery tube and collected over a basin of water using a beehive shelf. |
Describe the physical properties of ethene. | Ethene is a colourless gas with a sweet smell
Its insoluble in water but dissolves in non-polar solvents eg- Cyclohexane
(like dissolves like) |
What is combustion? | Burning in oxygen |
Describe the procedure for the combustion of ethene. | Place a lighted splint into a test tube of ethene gas. Add lime water to the test tube, stopper and shake |
What is the positive result of the combustion of ethene? | Ethene burns with a bright yellow flame
Limewater turns milky white proving CO2 was formed in the combustion |
Write a balanced chemical equation for the complete combustion of ethene. | C2H4 + 3O2 -> 2CO2 + 2H2O |
Write a balanced chemical equation to explain why CO2 turns limewater white. | CO2 + Ca (OH)2 -> CaCO3 downwards arrow
Carbon dioxide + limewater(calcium hydroxide) -> calcium carbonate |
Describe the test to see if ethene is unsaturated using bromine water. | Add red bromine water to a test tube of ethene gas, stopper and shake
Result: red bromine water turns colourless - ethene is unsaturated
(is anything was saturated it would remain red) |
What type of reaction occurs when bromine is added to ethene gas? | Addition reaction- the adding of a bromine molecules across a double bond, breaking the double bond |
Write a balanced equation for the test for unsaturation using bromine water. | Ethene + bromine -> 1,2 dibromoethane
C2H4 + Br2 -> C2H4Br2 |
Explain how to test for unsaturation using acidified potassium manganate VII and give the positive result. | Add purple KMnO4 / acidified potassium manganate VII, stopper and shake.
Purple acidified potassium manganate (VII) turns colourless
Ethene is unsaturated |
What type of reaction is the preparation of ethene known as? | Elimination / dehydration reaction |
What is the function of the aluminium oxide in the testing of the properties of ethene? | Aluminium oxide acts as a dehydrating agent
Is a catalyst for the reaction |
What is the appearance of aluminium oxide? | White powder |
Why is the aluminium oxide heated gently/ why is the ethanol not heated directly? | To avoid the ethanol vaporising too quickly and passing over the aluminium oxide too quickly - little ethanol would be converted into ethene |