ilica) B1\n- Identify the other condition: Slight pressure / moderate pressure (e.g., $1\\text{--}5\\text{ atm}$ or $100\\text{--}500\\text{ kPa}$) B1\n- State the equation: $\\text{C}_{14}\\text{H}_{30} \\rightarrow \\text{C}_7\\text{H}_{16} + \\text{C}_5\\text{H}_{10} + \\text{C}_2\\text{H}_4$ A1","marks":3,"order":1,"markingRubric":null,"explanation":{"methods":[{"id":"recall_and_mass_balance","label":"Recall and Mass Balance","steps":[{"type":"text","order":0,"title":"Recall catalyst and conditions","content":"To answer the first two parts, we recall the industrial conditions used for **catalytic cracking**:\n\n* **Catalyst:** A **zeolite** (or aluminosilicate, aluminium oxide, silica, alumina).\n* **Other condition:** **Slight pressure** (or moderate pressure, approximately $1\\text{--}5\\text{ atm}$ or $100\\text{--}500\\text{ kPa}$).\n\n*(Note: High temperature is also a key condition, which is already given in the question prompt.)*"},{"type":"text","order":1,"title":"Determine reactant & product formulas","content":"Now we need to write the chemical equation. Let's write down the molecular formulas of our reactant and the known products:\n\n* **Reactant:** Tetradecane $\\rightarrow \\text{C}_{14}\\text{H}_{30}$\n* **Product 1:** Heptane (an alkane with 7 carbons) $\\rightarrow \\text{C}_7\\text{H}_{16}$\n* **Product 2:** Cyclopentane (a cyclic alkane with 5 carbons) $\\rightarrow \\text{C}_5\\text{H}_{10}$"},{"type":"hyper_latex","block":{"nodes":[{"latex":"$$\\text{Reactant atoms: } \\htmlData{anchor=rect-c}{\\color{@sky}{14\\text{ C}}}, \\; \\htmlData{anchor=rect-h}{\\color{@amber}{30\\text{ H}}}$"},{"latex":"$$\\text{Known products: } \\htmlData{anchor=prod-c}{\\color{@sky}{(7 + 5)\\text{ C}}} \\text{ and } \\htmlData{anchor=prod-h}{\\color{@amber}{(16 + 10)\\text{ H}}}$"},{"latex":"$$\\text{Remaining atoms: } \\htmlData{anchor=rem-c}{\\color{@sky}{2\\text{ C}}}, \\; \\htmlData{anchor=rem-h}{\\color{@amber}{4\\text{ H}}}$"}],"highlights":[{"color":"sky","style":"box","anchor":"rem-c"},{"color":"amber","style":"box","anchor":"rem-h"}],"connections":[{"to":"prod-c","from":"rect-c","color":"sky","label":"subtract carbons","style":"solid"},{"to":"prod-h","from":"rect-h","color":"amber","label":"subtract hydrogens","style":"solid"}]},"order":2,"title":"Perform mass balance","description":"Subtract the number of carbon and hydrogen atoms of the known products from the starting reactant, tetradecane, to find the formula of the third product."},{"type":"text","order":3,"title":"Write the balanced equation","content":"Since the remaining atoms are $2$ carbons and $4$ hydrogens, the third product must be ethene with the formula $\\text{C}_2\\text{H}_4$.\n\nCombining everything, the balanced chemical equation is:\n\n$$\\text{C}_{14}\\text{H}_{30} \\rightarrow \\text{C}_7\\text{H}_{16} + \\text{C}_5\\text{H}_{10} + \\text{C}_2\\text{H}_4$$"}]}],"generatedAt":"2026-06-11T09:28:08.399Z","modelVersion":"gemini-3.5-flash","explanationVersion":"v2"},"options":[]},{"id":"01ec5dad-77b3-4b03-a14d-cc696abb2748","label":"3","content":"Alkanes can undergo free-radical substitution reactions to form halogenoalkanes.\nGive equations for the propagation steps in the reaction of butane to form 2-chlorobutane.","markscheme":"- First propagation step showing chlorine radical reacting with butane to form a secondary butyl radical and hydrogen chloride: $\\text{Cl}^\\bullet + \\text{CH}_3\\text{CH}_2\\text{CH}_2\\text{CH}_3 \\rightarrow \\text{CH}_3\\dot{\\text{C}}\\text{HCH}_2\\text{CH}_3 + \\text{HCl}$ M1\n- Second propagation step showing the butyl radical reacting with chlorine to form 2-chlorobutane and regenerating the chlorine radical: $\\text{CH}_3\\dot{\\text{C}}\\text{HCH}_2\\text{CH}_3 + \\text{Cl}_2 \\rightarrow \\text{CH}_3\\text{CHClCH}_2\\text{CH}_3 + \\text{Cl}^\\bullet$ A1","marks":2,"order":2,"markingRubric":null,"explanation":{"methods":[{"id":"condensed_structural","label":"Using Condensed Structural Formulas","steps":[{"type":"text","order":0,"t

Halogenoalkanes

Question 3

Halogenoalkanes Questions

Halogenoalkanes

Question 3

Halogenoalkanes Questions