6.3. Reversible reactions and equilibrium
A subsection of Chemistry, 0620, through 6. Chemical reactions
Listing 10 of 390 questions
This question is about sulfur and its compounds. Natural gas contains hydrocarbons and hydrogen sulfide. Give the name of the hydrocarbon which is present in the greatest concentration in natural gas. Hydrogen sulfide is removed from natural gas by reaction with oxygen in the presence of a catalyst. What is the purpose of a catalyst? Name the acid manufactured from sulfur. When fossil fuels containing sulfur are burned, sulfur dioxide is formed. Sulfur dioxide contributes to acid rain. Give one harmful effect of acid rain on buildings. Sulfur dioxide is oxidised by nitrogendioxide in the atmosphere to form sulfurtrioxide. SO2 + NO2 SO3 + NO How does this equation show that sulfur dioxide is oxidised? 
0620_m18_qp_32
THEORY
2018
Paper 3, Variant 2
View
This question is about sulfur, sulfur compounds and the water from a sulfur spring. A sulfur spring is a natural source of water containing sulfur. The table shows the mass of ions present in a 1000 cm3 sample of water from a sulfur spring. ion present formula of ion mass present in the 1000 cm3 sample / mg Br – calcium Ca2+ chloride Cl – fluoride F – iron(Fe3+ magnesium Mg2+ K+ sodium Na+ sulfate SO4 2– Answer these questions using only information from the table. Which negative ion is present in the lowest concentration? Give the name of the compound formed from only K+ and Br – ions. Calculate the mass of calcium ions present in a 250 cm3 sample of this water.  mass of calcium ions = mg Complete the equation to show the formation of a fluoride ion from a fluorine atom. F + F –  Describe a test for sulfate ions. test observations  Solid sulfur is found around the edge of sulfur springs. When heated, sulfur undergoes sublimation. What is meant by the term sublimation? Sulfur reacts with hot concentrated sulfuric acid. Complete the chemical equation for this reaction. S + H2SO4 2H2O + SO2 The table shows the solubility of sulfur and zinc in an organic solvent and in water. The organic solvent boils at 46 °C. element solubility in organic solvent solubility in water sulfur soluble insoluble zinc insoluble insoluble Use the information in the table to suggest how to obtain pure, dry samples of both sulfur and zinc from a mixture of sulfur powder and zinc powder. The structure of a sulfur compound is shown. S F F F F O F F Deduce the molecular formula of this compound showing the number of sulfur, fluorine and oxygen atoms. 
0620_m19_qp_32
THEORY
2019
Paper 3, Variant 2
View
This question is about sulfur and compounds of sulfur. Sulfur is a non-metal. Describe three physical properties which are typical of non-metals.  Name one source of sulfur. When carbon is heated with sulfur, carbondisulfide, CS2, is produced. C + 2S → CS2 Complete the energy level diagram for the production of carbondisulfide by writing these formulae on the diagram: ● C + 2S ● CS2. energy progress of reaction  Explain, using information on the energy level diagram, how you know that this reaction is endothermic. Carbondisulfide is a liquid at room temperature. Describe the separation and motion of the particles in carbondisulfide liquid. separation motion  Hydrogensulfide is a gas which turns filter paper soaked in aqueous lead(ethanoate from white to black. Hydrogen sulfide is slightly soluble in water. A long glass tube is set up as shown. long glass tube cotton wool soaked in aqueous hydrogen sulfide filter paper soaked in aqueous lead(ethanoate At first, the filter paper soaked in aqueous lead(ethanoate does not turn black. After a short time, the filter paper soaked in aqueous lead(ethanoate turns black. Explain these observations using the kinetic particle model. Sulfurdioxide is a pollutant in the air. Give one adverse effect of sulfurdioxide on buildings. Sulfurdioxide is used to bleach paper. Give one other use of sulfurdioxide. 
0620_m21_qp_32
THEORY
2021
Paper 3, Variant 2
View
Sulfur is an element in Group VI of the Periodic Table. State the meaning of the term element. Sulfur has a relative atomic mass of 32. Complete these sentences about the relative atomic mass of sulfur using terms from the list. 12C electrons 1H isotopes neutrons 16O protons 32S The relative atomic mass of sulfur is the average mass of the sulfur . This average mass is compared to 1/12th of the mass of an atom of .  Sulfur is a solid at room temperature and pressure. Describe the motion and separation of the particles in solid sulfur. motion separation  Liquid sulfur reacts with chlorine to produce disulfur dichloride. 2S + Cl 2 → S2Cl 2 Describe how the general physical properties of a liquid differ from those of a solid. Give two differences.  When 6.4 g of sulfur reacts with excess chlorine, 13.5 g of disulfur dichloride is produced. Calculate the mass of disulfur dichloride produced when 19.2 g of sulfur reacts with excess chlorine.  mass = g Sulfur dioxide is formed when sulfur burns in air. State the percentage of oxygen in clean, dry air. State one source of the pollutant sulfur dioxide in the air other than from burning sulfur. State one adverse effect of sulfur dioxide in the air. State one method of reducing the emissions of sulfur dioxide. Sulfur dioxide dissolves in water to form sulfurous acid. Give the formula of the ion that is present in all aqueous acids. Sulfur dioxide reacts with oxygen in the presence of a catalyst to form sulfur trioxide. This is a reversible reaction. Complete the equation for this reaction by writing the sign for a reversible reaction in the box. 2SO2 + O2 2SO3 
0620_m24_qp_32
THEORY
2024
Paper 3, Variant 2
View
Questions Discovered
390