(a) What is meant by hydrocarbon?
Step 1: Hydrocarbon is a compound composed of hydrogen and carbon atoms only. †Answer: Answer: Hydrocarbon is a compound consisting of hydrogen and carbon atoms only.
(b) Identify compounds P, Q, and R. State the homologous series and draw the structural formula of compounds P, Q, and R.
Step 1: Compound P is ethanol (C2H5OH). Step 2: Compound Q is ethene (C2H4). Step 3: Compound R is ethanoic acid (CH3COOH). Step 4: Homologous series: Alcohols for P, Alkenes for Q, Carboxylic acids for R. Step 5: Structural formulas:
- Compound P (Ethanol): CH3CH2OH
- Compound Q (Ethene): CH2=CH2
- Compound R (Ethanoic acid): CH3COOH †Answer: Answer: Compound P: Ethanol, C2H5OH Compound Q: Ethene, C2H4 Compound R: Ethanoic acid, CH3COOH
(c) Write the chemical equation for Reaction II. If 480 cm3 of compound P is used, calculate the volume of compound Q produced. (1 mol of gas occupies 24 dm3 at room temperature)
Step 1: Chemical equation for Reaction II:
- C2H5OH (Ethanol) -> C2H4 (Ethene) + H2O (Water) Step 2: Calculate the number of moles of compound P:
- Volume of compound P = 480 cm3 = 0.48 dm3
- Moles of compound P = Volume / Molar volume = 0.48 dm3 / 24 dm3/mol = 0.02 mol Step 3: Since the reaction is 1:1, the volume of compound Q produced will be the same as the volume of compound P used. †Answer: Answer: Chemical equation: C2H5OH -> C2H4 + H2O Volume of compound Q produced: 0.48 dm3
(d) Ethanol can be converted into compound R through Reaction III. State the type of reaction and the method used in the conversion, and state the color changes of acidified potassium dichromate (VI) solution. Draw a flowchart of the conversion of ethanol to compound P via Reaction I.
Step 1: Type of reaction for Reaction III: Oxidation Step 2: Method used: Acidified potassium dichromate (VI) solution is used as an oxidizing agent. Step 3: Color changes of acidified potassium dichromate (VI) solution: Orange to green Step 4: Flowchart of the conversion of ethanol to compound P via Reaction I: Ethanol (C2H5OH) -> Compound Q (C2H4) + H2O †Answer: Answer: Type of reaction: Oxidation Method used: Acidified potassium dichromate (VI) solution Color changes: Orange to green
