9. Metals
A section of Chemistry, 0620
Listing 10 of 1272 questions
The structure of tartaric acid is shown. C C H O O H O H H O C C H O O H On the structure, draw a circle around one alcohol functional group. Deduce the formula of tartaricacid to show the number of carbon, hydrogen and oxygen atoms. Complete the table to calculate the relative molecular mass of tartaricacid. Use your Periodic Table to help you. type of atom number of atoms relative atomic mass carbon hydrogen 6 × 1 = 6 oxygen  relative molecular mass = Acids react with bases such as calciumhydroxide. Complete the word equation for the reaction of nitricacid with calciumhydroxide. nitric acid + calcium hydroxide +  An aqueous solution of calciumhydroxide is alkaline. Identify which one of these pH values represents the pH of an alkaline solution. Draw a circle around the correct answer. pH 1 pH 4 pH 7 pH 10 One way of determining pH is to use a pH meter. Describe one other way of determining pH. Farmers spread calciumhydroxide (slaked lime) on fields where crops are grown. Explain why. Calciumcarbonate undergoes thermal decomposition. CaCO3 → CaO + CO2 State the meaning of the term thermal decomposition. Complete the energy level diagram for the thermal decomposition of calciumcarbonate by writing these words on the diagram: ● ● reactant ● ● products. energy progress of reaction  Explain, using information on the energy level diagram, how you know that this reaction is endothermic. 
0620_w20_qp_31
THEORY
2020
Paper 3, Variant 1
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This question is about metals and compounds of metals. Sodium is a metal in GroupI of the Periodic Table. Identify two correct statements about sodium. Tick two boxes. It is a relatively soft metal. It has a high melting point. It forms coloured chlorides. It has a lower density than most metals. It is a good insulator.  Some changes of state of sodium are shown. solid sodium melting R liquid sodium sodium gas S condensing Give the names of the changes of state represented by R and S. R S  The table compares the reactions of four metals with dilute and with concentrated hydrochloricacid. metal observation with dilute hydrochloric acid observation with concentrated hydrochloric acid beryllium bubbles form rapidly bubbles form very rapidly copper no bubbles seen no bubbles seen iron bubbles form very slowly bubbles form slowly nickel no bubbles seen bubbles form slowly Put the four metals in order of their reactivity. Put the least reactive metal first. least reactive most reactive  Crystals of magnesium chloride, MgCl 2•6H2O, can be prepared by adding excess magnesium powder to dilute hydrochloricacid. Describe how to prepare a sample of pure dry magnesiumchloride crystals after the reaction is complete. In your answer describe how to: ● ● remove the excess magnesium from the reaction mixture ● ● crystallise the magnesiumchloride ● ● dry the crystals. When magnesium reacts with concentrated sulfuricacid, sulfurdioxide is produced. Complete this description of the test for sulfurdioxide using words from the list. blue chloride colourless green manganate(sulfate(The test for sulfurdioxide uses acidified aqueous potassium . The colour change is from purple to .  Green nickel(sulfate crystals turn yellow when heated. NiSO4•7H2O NiSO4 + 7H2O green yellow nickel(sulfate nickel(sulfate Suggest how you would change yellow nickel(sulfate to green nickel(sulfate. Identify which word best describes green nickel(sulfate with the formula NiSO4•7H2O. Draw a circle around the correct answer. anhydrous decomposed hydrated oxidised reduced 
0620_w20_qp_33
THEORY
2020
Paper 3, Variant 3
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Zinc is extracted from an ore containing zinc sulfide. State the name of this zinc ore. This ore is converted to zincoxide, ZnO. Zincoxide is then reacted with carbon. Write a chemical equation for the reaction of zincoxide with carbon. State what type of chemical change happens to the zinc in zincoxide in this reaction. Explain your answer. chemical change explanation  Explain why aluminium is not extracted from aluminiumoxide by heating with carbon. Suggest an alternative method for the extraction of zinc from zincoxide. Brass is an alloy of zinc. Explain, in terms of particles, why brass is harder than pure zinc. 
0620_w20_qp_41
THEORY
2020
Paper 4, Variant 1
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Zinc is manufactured from zincblende. Zincblende is an ore which consists mainly of zincsulfide, ZnS. Zincblende is roasted in air. One of the products is zincoxide. Name the other product formed in this reaction. Zincoxide is then converted into zinc. Zincoxide and coke, a source of carbon, are heated in a furnace. Hot air is blown into the furnace. Give two reasons why coke is needed.  Write a chemical equation for the formation of zinc in the furnace. Zinc has a melting point of 420 °C and a boiling point of 907 °C. The temperature inside the furnace is 1200 °C. Explain how this information shows that the zinc produced inside the furnace is a gas. The gaseous zinc is converted to molten zinc. Name this change of state. Zinc reacts with dilute sulfuricacid to produce aqueous zincsulfate. Zn+ H2SO4→ ZnSO4+ H2Hydrated zincsulfate crystals are made from aqueous zincsulfate. Step 1 Solid zinc is added to dilute sulfuricacid until zinc is in excess. Step 2 Excess zinc is separated from aqueous zincsulfate by filtration. Step 3 Aqueous zincsulfate is heated until the solution is saturated. Step 4 The saturated solution is allowed to cool and crystallise. Step 5 The crystals are removed and dried. Name the residue in step2. In step3, a saturated solution is produced. Describe what a saturated solution is. Name two compounds each of which react with dilute sulfuricacid to produce aqueous zincsulfate.  When hydrated magnesiumsulfate crystals, MgSO4•xH2O, are heated they give off water. MgSO4•xH2O→ MgSO4+ xH2OA student carries out an experiment to determine the value of x in MgSO4•xH2O. Step 1 Hydrated magnesiumsulfate crystals were weighed. Step 2 Hydrated magnesiumsulfate crystals were heated. Step 3 The remaining solid was weighed. Describe how the student can ensure that all the water is given off. In an experiment, all the water was removed from 1.23 g of MgSO4•xH2O. The mass of MgSO4 remaining was 0.60 g. Mr: MgSO4 = 120; Mr: H2O = 18 Determine the value of x using the following steps. ● Calculate the number of moles of MgSO4 remaining.  moles of MgSO4 = ● Calculate the mass of H2O given off.  mass of H2O = g ● Calculate the moles of H2O given off.  moles of H2O = ● Determine the value of x.  x =  
0620_w20_qp_43
THEORY
2020
Paper 4, Variant 3
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GroupI elements, GroupVII elements and transition elements are found in different parts of the Periodic Table. Describe the trend in the reactivity of GroupI elements. When potassium is added to water a chemical reaction occurs. State two observations that can be made when potassium is added to water. Write a chemical equation for the reaction of potassium with water. Excess aqueous potassiumiodide is added to chlorine. Write a chemical equation for the reaction that occurs when aqueous potassiumiodide is added to chlorine. State the final colour of the reaction mixture. Sodium is extracted from sodiumchloride by electrolysis. State the meaning of the term electrolysis. State what must be done to sodiumchloride before it can be electrolysed to produce sodium. Write an ionic half-equation for the change that occurs at the cathode during this electrolysis. Chromium is a transition element. ● Chromium has a high melting point. ● Chromium is a good conductor of electricity. ● Many chromium compounds are soluble in water. ● Hydrated chromium(sulfate is green. ● Chromium forms the chlorides CrCl 2 and CrCl 3. ● Oxides of chromium act as catalysts in the manufacture of poly. Use this information to give two properties of chromium which are different from properties of GroupI elements such as sodium.  Use this information to give two properties of chromium which are similar to properties of GroupI elements such as sodium.  
0620_w20_qp_43
THEORY
2020
Paper 4, Variant 3
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Questions Discovered
1272