Chemistry Summer Holiday Homework Year Y9 & 10

Transcription

1 Chemistry Summer Holiday Homework Year Y9 & An atom of aluminium has the symbol (a) Give the number of protons, neutrons and electrons in this atom of aluminium. Number of protons... Number of neutrons... Number of electrons... (3) (b) Why is aluminium positioned in Group 3 of the periodic table? (c) In the periodic table, the transition elements and Group 1 elements are metals. Some of the properties of two transition elements and two Group 1 elements are shown in the table below. Transition elements Group 1 elements Chromium Iron Sodium Caesium Melting point in C Formula of oxides CrO FeO Na2O Cs2O Cr2O3 Fe2O3 CrO2 Fe3O4 CrO3 Use your own knowledge and the data in the table above to compare the chemical and physical properties of transition elements and Group 1 elements. 1

2 2. Rock salt is a mixture of sand and salt. Salt dissolves in water. Sand does not dissolve in water. Some students separated rock salt. This is the method used. 1. Place the rock salt in a beaker. 2. Add 100 cm 3 of cold water. 3. Allow the sand to settle to the bottom of the beaker. 4. Carefully pour the salty water into an evaporating dish. 5. Heat the contents of the evaporating dish with a Bunsen burner until salt crystals start to form. (6) (Total 10 marks) (a) Suggest one improvement to step 2 to make sure all the salt is dissolved in the water. (b) The salty water in step 4 still contained very small grains of sand. Suggest one improvement to step 4 to remove all the sand. (c) Suggest one safety precaution the students should take in step 5. 2

3 (d) Another student removed water from salty water using the apparatus in the figure below. Describe how this technique works by referring to the processes at Aand B. (2) (e) What is the reading on the thermometer during this process?. C... (Total 6 marks) 3. This question is about halogens and their compounds. The table below shows the boiling points and properties of some of the elements in Group 7 of the periodic table. Element Boiling point in C Colour in aqueous solution Fluorine 188 colourless Chlorine 35 pale green Bromine X orange Iodine 184 brown (a) Why does iodine have a higher boiling point than chlorine? Tick one box. 3

4 Iodine is ionic and chlorine is covalent Iodine is less reactive than chlorine The covalent bonds between iodine atoms are stronger The forces between iodine molecules are stronger (b) Predict the boiling point of bromine..... (c) A redox reaction takes place when aqueous chlorine is added to potassium iodide solution. The equation for this reaction is: Cl2(aq) + 2KI(aq) I2 (aq) + 2KCl(aq) Look at table above. What is the colour of the final solution in this reaction? Tick one box. Brown Orange Pale green Colourless (d) What is the ionic equation for the reaction of chlorine with potassium iodide? Tick one box. Cl2 + 2K 2KCl 2I + Cl2 I2 + 2Cl 4

5 I + Cl I + Cl I + K + KI (e) Why does potassium iodide solution conduct electricity? Tick one box. It contains a metal It contains electrons which can move It contains ions which can move It contains water (f) What are the products of electrolysing potassium iodide solution? Tick one box. Product at cathode hydrogen Product at anode iodine hydrogen oxygen potassium iodine potassium oxygen (Total 6 marks) 4. Marble chips are mainly calcium carbonate (CaCO3). A student investigated the rate of reaction between marble chips and hydrochloric acid (HCl). Figure 1 shows the apparatus the student used. Figure 1 5

6 (a) Complete and balance the equation for the reaction between marble chips and hydrochloric acid CaCl (2) (b) The table below shows the student s results. Time in s Volume of gas in dm On Figure 2: Plot these results on the grid. Draw a line of best fit. Figure 2 6

7 (4) (c) Sketch a line on the grid in Figure 2 to show the results you would expect if the experiment was repeated using 20 g of smaller marble chips. Label this line A. (2) (d) Explain, in terms of particles, how and why the rate of reaction changes during the reaction of calcium carbonate with hydrochloric acid. (4) (e) Another student investigated the rate of reaction by measuring the change in mass. Figure 3 shows the graph plotted from this student s results. Figure 3 7

8 Use Figure 3 to calculate the mean rate of the reaction up to the time the reaction is complete. Give your answer to three significant figures. / s Mean rate of reaction =... g (4) (f) Use Figure 3 to determine the rate of reaction at 150 seconds. Show your working on Figure 3. Give your answer in standard form. 8

9 Rate of reaction at 150 s =... g / s (4) (Total 20 marks) 5. There are eight elements in the second row (lithium to neon) of the periodic table. (a) Figure 1 shows an atom with two energy levels (shells). (i) Complete Figure 1 to show the electronic structure of a boron atom. (ii) What does the central part labelled Z represent in Figure 1?... (iii) Name the sub-atomic particles in part Z of a boron atom. Give the relative charges of these sub-atomic particles. (3) (b) The electronic structure of a neon atom shown in Figure 2 is notcorrect. 9

10 Explain what is wrong with the electronic structure shown in Figure 2. (3) (Total 8 mark) 6. This question is about fluorine. (a) Figure 1 shows the arrangement of electrons in a fluorine atom. (i) In which group of the periodic table is fluorine? Group... (ii) Complete the table below to show the particles in an atom and their relative masses. 10

11 Name of particle Relative mass Proton Neutron 1 Very small (2) (iii) Use the correct answer from the box to complete the sentence. alkalis alloys isotopes Atoms of fluorine with different numbers of neutrons are called.... (b) Sodium reacts with fluorine to produce sodium fluoride. (i) Complete the word equation for this reaction. sodium (ii) Complete the sentence. Substances in which atoms of two or more different elements are chemically combined are called.... (iii) The relative formula mass (Mr) of sodium fluoride is 42. Use the correct answer from the box to complete the sentence. ion mole molecule The relative formula mass (Mr), in grams, of sodium fluoride is one... of the substance. (iv) Figure 2 shows what happens to the electrons in the outer shells when a sodium atom reacts with a fluorine atom. The dots ( ) and crosses ( ) represent electrons. 11

12 Use Figure 2 to help you answer this question. Describe, as fully as you can, what happens when sodium reacts with fluorine to produce sodium fluoride. (4) (v) Sodium fluoride is an ionic substance. What are two properties of ionic substances? Tick ( ) two boxes. Dissolve in water Gas at room temperature High melting point Low boiling point (2) (Total 13 marks) 7. This question is about atoms, molecules and nanoparticles. (a) Different atoms have different numbers of sub-atomic particles. 12

13 (i) An oxygen atom can be represented as O Explain why the mass number of this atom is 16. You should refer to the numbers of sub-atomic particles in the nucleus of the atom. (2) (ii) Explain why C and C are isotopes of carbon. You should refer to the numbers of sub-atomic particles in the nucleus of each isotope. (3) (b) Hydrogen atoms and oxygen atoms chemically combine to produce water molecules. (i) Complete the figure below to show the arrangement of the outer shell electrons of the hydrogen and oxygen atoms in a molecule of water. Use dots ( ) or crosses ( ) to represent the electrons. (2) (ii) Name the type of bonding in a molecule of water. 13

14 (iii) Why does pure water not conduct electricity? (c) Nanoparticles of cobalt oxide can be used as catalysts in the production of hydrogen from water. (i) How does the size of a nanoparticle compare with the size of an atom? (ii) Suggest one reason why 1 g of cobalt oxide nanoparticles is a better catalyst than 1g of cobalt oxide powder. (Total 11 marks) 8. This question is about elements and the periodic table. (a) Newlands and Mendeleev both produced early versions of the periodic table. (i) Complete the sentence. In their periodic tables, Newlands and Mendeleev arranged the elements in order of.... (ii) Name the particle that allowed the elements to be arranged in order of their atomic number in the modern periodic table.... (b) The diagram below shows the position of nine elements in the modern periodic table. 14

15 (i) Which one of the nine elements shown in the diagram above has the lowest boiling point? (ii) Copper and potassium have different melting points and boiling points. Give one other difference between the properties of copper and potassium. (iii) Explain why the reactivity of the elements increases going down Group 1 from lithium to rubidium but decreases going down Group 7 from fluorine to iodine. (4) (Total 8 marks) 15

16 9. In 1866 John Newlands produced an early version of the periodic table. Part of Newlands periodic table is shown below. Column H Li Be B C N O F Na Mg Al Si P S Cl K Ca Cr Ti Mn Fe Newlands periodic table arranged all the known elements into columns in order of their atomic weight. Newlands was trying to show a pattern by putting the elements into columns. (a) Iron (Fe) does not fit the pattern in column 7. Give a reason why (b) In 1869 Dmitri Mendeleev produced his version of the periodic table. Why did Mendeleev leave gaps for undiscovered elements in his periodic table? (c) Newlands and Mendeleev placed the elements in order of atomic weight. Complete the sentence. The modern periodic table places the elements in order of.... (d) Lithium, sodium and potassium are all in Group 1 of the modern periodic table. Explain why

17 (2) (Total 5 marks) 10. Sulfur is a non-metal. Sulfur burns in the air to produce sulfur dioxide, SO 2 (a) Why is it important that sulfur dioxide is not released into the atmosphere? Tick ( ) one box. Sulfur dioxide causes acid rain. Sulfur dioxide causes global dimming. Sulfur dioxide causes global warming. (b) Sulfur dioxide dissolves in water. What colour is universal indicator in a solution of sulfur dioxide? Give a reason for your answer (2) (c) Sulfur dioxide is a gas at room temperature. The bonding in sulfur dioxide is covalent. Explain, in terms of its structure and bonding, why sulfur dioxide has a low boiling point

18 (3) (d) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. Sulfur dioxide is produced when fossil fuels are burned. It is important that sulfur dioxide is not released into the atmosphere. Three of the methods used to remove sulfur dioxide from gases produced when fossil fuels are burned are: wet gas desulfurisation (W) dry gas desulfurisation (D) seawater gas desulfurisation (S). Information about the three methods is given in the bar chart and in Table 1 and Table 2. Method of removing sulfur dioxide Table 1 Method Material used How material is obtained W Calcium carbonate, CaCO 3 Quarrying D Calcium oxide, CaO Thermal decomposition of calcium carbonate: CaCO 3 CaO + CO 2 S Seawater From the sea Table 2 Method What is done with waste material 18

19 W Solid waste is sold for use in buildings. Carbon dioxide is released into the atmosphere. D Solid waste is sent to landfill. S Liquid waste is returned to the sea. Evaluate the three methods of removing sulfur dioxide from waste gases. Compare the three methods and give a justified conclusion (6) (Total 12 marks) 19

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