8.3. Group VII properties
A subsection of Chemistry, 0620, through 8. The Periodic Table
Listing 10 of 123 questions
The Group VII elements are called the halogens. Describe the trends in • the physical properties of the halogens, • the reactivity of halogens with other halide ions. Include a relevant word equation in your answer. Iodine reacts with hot concentrated nitric acid. I2 10HNO3 2HIO3 4H2O 10NO2 Explain why this reaction could have an adverse effect on health if not carried out in a fume cupboard. Nitric acid is strongly acidic. Which one of the following pH values represents a strongly acidic solution? Put a ring around the correct answer. pH 13 D pH 9 C pH 7 B pH 1 A [ 1 11 Nitric acid reacts with zinc oxide. State the names of the products of this reaction. and
0620_s16_qp_31
THEORY
2016
Paper 3, Variant 1
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Chlorine, bromine and iodine are halogens. The melting point of bromine is –7ºC. The boiling point of bromine is +59ºC. Deduce the state of bromine at +6ºC. Explain your answer. Complete the word equation for the reaction of chlorine with potassium iodide. chlorine + potassium iodide → + Suggest why iodine does not react with aqueous potassium bromide. The structure of the dye Lithol fast yellow is shown. C C C C O O C C Cl Cl H H N H H H C H H N H N H O O N C C C C C C H Complete the table and calculate the relative molecular mass of Lithol fast yellow. atomic mass number of atoms type of atom 13 × 12 = 156 carbon 10 × 1 = 10 hydrogen 4 × 14 = 56 nitrogen oxygen chlorine relative molecular mass = 1 12 Chromatography is used to separate a mixture of dyes. Draw a cross on the diagram to show where the mixture of dyes is placed at the start of the chromatography. solvent Suggest a suitable solvent that could be used. Describe what you would observe as the experiment proceeds. [ 1 12
0620_s16_qp_32
THEORY
2016
Paper 3, Variant 2
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The elements in Group VII are known as the halogens. Some halogens react with aqueous solutions of halides. Complete the table by adding a  to indicate when a reaction occurs and a  to indicate when no reaction occurs. aqueous potassium chloride aqueous potassium bromide aqueous potassium iodide chlorine   bromine  iodine  Write a chemical equation for the reaction between chlorine and aqueouspotassiumbromide. A sample of vanadium chloride was weighed and dissolved in water. An excess of aqueous silvernitrate, acidified with dilute nitric acid, was added. A precipitate of silver chloride was formed. The ionic equation for this reaction is shown. Ag++ Cl –AgCl The mass of silver chloride formed was 2.87 g. State the colour of the precipitate of silver chloride. The relative formula mass of silver chloride, AgCl, is 143.5. Calculate the number of moles in 2.87 g of AgCl. moles of AgCl = mol Use your answer to and the ionic equation to deduce the number of moles of chloride ions, Cl –, that produced 2.87 g of AgCl. moles of Cl – = mol The amount of vanadium chloride in the sample was 0.01 moles. Use this and your answer to to deduce the whole number ratio of moles of vanadiumchloride : moles of chloride ions. Deduce the formula of vanadium chloride. moles of vanadium chloride : moles of chloride ions : formula of vanadium chloride Astatine is at the bottom of Group VII. Use your knowledge of the properties of the halogens to predict the physical state of astatine at room temperature and pressure, write a chemical equation for the reaction between sodium and astatine. Iodine reacts with chlorine. The chemical equation is shown. I2 + Cl 2 2ICl Use the bond energies to answer the questions. bond bond energy in kJ / mol I–I Cl –Cl I–Cl Calculate the total amount of energy required to break the bonds in 1mole of I2 and 1mole of Cl 2. kJ Calculate the total amount of energy given out when the bonds in 2moles of ICl are formed. kJ Use your answers to and to calculate the overall energy change for the reaction. I2 + Cl 2 2ICl kJ / mol
0620_s17_qp_42
THEORY
2017
Paper 4, Variant 2
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The properties of some GroupVII elements are shown in the table. element melting point in °C boiling point in °C density at room temperature in g / cm3 colour chlorine –101 –35 0.0032 green bromine –7 3.1 red-brown iodine grey-black astatine 6.4 Complete the table to suggest: ● ● the density of iodine ● ● the melting point of astatine ● ● the colour of astatine.  Suggest why the density of chlorine at room temperature is much lower than the density of bromine and astatine at room temperature. Describe the trend in the boiling points of the halogens. Aqueous bromine reacts with aqueous potassium iodide. Complete the word equation for this reaction. bromine + potassium iodide +  A compound has the formula C2F4Cl 2. Calculate the relative molecular mass of C2F4Cl 2. Show all your working. Use your Periodic Table to help you.  relative molecular mass = 
0620_s18_qp_32
THEORY
2018
Paper 3, Variant 2
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