IGCSE CHEMISTRY STUDY GUIDE EXAM 2024.

IGCSE CHEMISTRY STUDY GUIDE EXAM 2024. State the name of the gas formed at the anode during the electrolysis sodium chloride solution. (Triple science only!) - CORRECT ANSWER chlorine State the name of the gas formed at the cathode during the electrolysis sodium chloride solution. (Triple science only!) - CORRECT ANSWER hydrogen The solution formed after the electrolysis sodium chloride solution was tested with the indicator phenolphthalein. The indicator turned pink. Explain this result. (Triple science only!) - CORRECT ANSWER The solution is alkali (contains sodium hydroxide) In the electrolysis of brine, why is thelectrode made out of titanium? (Triple science only!) - CORRECT ANSWER To prevent it reacting with the chlorine Write the two ionic half-equations for the reactions that occur during the electrolysis of sodium chloride solution. (Triple science only!) - CORRECT ANSWER 2H⁺ + 2e⁻ → H₂ 2Cl⁻ → Cl₂ + 2e⁻ State the uses of sodium hydroxide. (Triple science only!) - CORRECT ANSWER manufacture of bleach, paper and soap State the uses of chlorine. (Triple science only!) - CORRECT ANSWER sterilising water supplies and the manufacture of bleach and hydrochloric acid Explain what is an addition polymer - CORRECT ANSWER An addition polymer is large molecule made by adding many small molecules (each containing a double bond) to form one much larger molecule Explain what is a monomer - CORRECT ANSWER Monomers are the many small molecules (such as ethene) which add together to make a polymer Describe, in terms of structure and bonding, what happens when ethene molecules are converted into poly(ethene) - CORRECT ANSWER One bond in the double bond breaks. Monomers join together to form a long chain. Polymer contains only single bonds Draw the equation to show the formation of poly(ethene) - CORRECT ANSWER Draw the equation to show the formation of poly(propene) - CORRECT ANSWER Draw the displayed formula for the repeat unit of poly(ethene) - CORRECT ANSWER Draw the displayed formula for the repeat unit of poly(propene) - CORRECT ANSWER Draw the displayed formula for the repeat unit of poly(chloroethene). (Triple science only!) - CORRECT ANSWER State the uses of poly(ethene) - CORRECT ANSWER Plastic bags and bottles State the uses of poly(propene) - CORRECT ANSWER Plastic crates and ropes State uses for poly(chloroethene). (Triple science only!) - CORRECT ANSWER Plastic piping and cable insulation What is meant by the term biodegradable? - CORRECT ANSWER The break down of a substance by microorganisms Explain why addition polymers are hard to dispose of - CORRECT ANSWER They are inert as they have strong C-C bonds. This makes them non-biodegradeable.