Alkane 烷烃
What is the general formula of alkanes?
A) CnH2n
B) CnH2n+2
C) CnH2n+1
D) CnH2n-2
B
What is the general formula of alkenes?
A) CnH2n
B) CnH2n+2
C) CnH2n+1
D) CnH2n-2
A
Which functional group is present in all alcohols?
A) -COOH
B) -OH
C) -COO-
D) -Cl
B) -OH
What is the functional group of carboxylic acids?
A) -OH
B) -COOH
C) -COO-
D) -CHO
B) -COOH
Esters are formed from the reaction between a carboxylic acid and which other compound?
A) Alkane
B) Alcohol
C) Alkene
D) Halogen
B) Alcohol
Which type of reaction occurs when methane reacts with chlorine in the presence of UV light?
A) Addition
B) Combustion
C) Substitution
D) Oxidation
C
Which reagent is used to test for the presence of a carbon-carbon double bond in alkenes?
A) Sodium hydroxide
B) Bromine water
C) Litmus paper
D) Potassium dichromate
B) Bromine water
What is the molecular formula of ethanol?
A) C2H5OH
B) C3H7OH
C) C2H4O
D) CH3COOH
A) C2H5OH
Which gas is produced when ethanoic acid reacts with magnesium?
A) Carbon dioxide
B) Hydrogen
C) Oxygen
D) Methane
B) Hydrogen
What is the name of the ester formed when methanol reacts with propanoic acid?
A) Methyl propanoate
B) Propyl methanoate
C) Ethyl ethanoate
D) Butyl butanoate
A) Methyl propanoate
Write the balanced equation for the complete combustion of propane in oxygen.
CH3CH2CH3(g) +5O2(g) → 3CO2(g) + 4H2O(l)
An alkene has 8 carbon atoms. Calculate its molecular formula and empirical formula。
molecular formula is C8H18
empirical formula is C4H9
Write the balanced equation for the complete combustion of Propanol ( C3H7OH ) in oxygen.
C3H7OH + 9/2O2→ 3CO2 + 4H2O
Write the equation for the reaction between ethanoic acid and sodium carbonate.
2CH3COOH + Na2CO3 → 2CH3COONa + CO2 + H2O
Write the equation for the reaction between ethanoic acid and ethanol to form an ester.
CH3COOH + C2H5OH → CH3COOC2H5 + H2O
Draw the equation when ethane reacts with chlorine in a substitution reaction, including condition (other product is HCl).
CH3CH3(g) +Cl2(g) → CH3CH2Cl(g) + HCl(l)
the reactions of alkanes with halogens in the presence of ultraviolet radiation(UV light)
Ethene (C2H4) reacts with bromine in an addition reaction. Draw the displayed structure of the product.
H H
| |
Br─C─C─Br
| |
H H
Compare the advantages and disadvantages of producing ethanol via fermentation vs the reaction of ethene with steam.
**Fermentation**: Renewable resources (sugar)
at an optimum temperature of about 30 ºC , but low yield.
**Ethene + steam**: Non-renewable (crude oil), in the presence of a phosphoric acid catalyst at a temperature of about 300 ºC, but high yield.
Draw the structural formula of propanoic acid.
Structural formula of propanoic acid:
CH3CH2COOH
Explain why esters are used in perfumes and food flavorings?
Esters are volatile and have pleasant, fruity aromas, making them ideal for perfumes and flavorings.
Explain why alkanes are described as "saturated" hydrocarbons?
Alkanes are saturated because all carbon-carbon bonds are single bonds, allowing each carbon atom to bond with the maximum number of hydrogen atoms.
Explain why alkenes are more reactive than alkanes？
Alkenes are more reactive due to the electron-rich C=C double bond, which can undergo addition reactions.
Explain why the oxidation of ethanol with acidified potassium dichromate(VI) produces ethanoic acid?
Acidified potassium dichromate(VI) oxidizes ethanol’s -OH group to -COOH, forming ethanoic acid.
Explain why carboxylic acids are weaker acids compared to hydrochloric acid?
Carboxylic acids only partially dissociate in water, releasing fewer H+ ions compared to strong acids like HCl.
Describe the steps to prepare ethyl ethanoate in a laboratory.
1. Mix ethanoic acid, ethanol, and concentrated H2SO4 .
2. Heat in a water bath at 60 0C .
3. Cool and pour into sodium carbonate solution.
4. Ester layer forms on top.