6. Chemical reactions
A section of Chemistry, 0620
Listing 10 of 905 questions
For Examiner's Use The diagram shows a statue in a park in an industrial town. The statue is made from limestone. iron pins inside statue statue when first erected the same statue after 20 years State the name of the chemical present in limestone. Use ideas about the chemistry of atmospheric pollutants to suggest how and why the statue changes over 20 years. Parts of the statue are joined together with iron pins. After 30 years, the arm falls off the statue. Suggest why the arm falls off. For Examiner's Use Iron has several isotopes. What do you understand by the term isotopes? The table shows the number of subatomic particles in an atom of iron. type of particle number of particles relative charge on the particle electron neutron proton Complete the table to show the relative charge on each particle. State the number of nucleons in this isotope of iron. Some isotopes are radioactive. State one industrial use of radioactive isotopes. Iron reacts with very dilute nitric acid. Fe + 2HNO3 Fe(NO3)2 + H2 Write a word equation for this reaction.
0620_s08_qp_2
THEORY
2008
Paper 2, Variant 0
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Potassium iodide is an ionic compound. Describe what happens, in terms of electron loss and gain, when a potassium atom reacts with an iodine atom. Describe the structure of solid potassium iodide. You may draw a diagram. Explain why potassium iodide has a high melting point. Potassium iodide and lead nitrate are both soluble. Lead iodide is insoluble. Describe how a pure dry sample of lead iodide could be made from solid potassiumiodide and solid lead nitrate. Write an ionic equation for the formation of lead iodide, PbI2, when potassiumiodide and lead nitrate react with each other. State symbols are not required. When chlorine gas is bubbled through an aqueous solution of potassium iodide, a redox reaction takes place. 2I – + Cl 2 → I2 + 2Cl – State the colour change expected in this reaction. start colour end colour Identify the reducing agent in this reaction. Explain your answer.
0620_s16_qp_43
THEORY
2016
Paper 4, Variant 3
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Questions Discovered
905