0620_w21_qp_42
A paper of Chemistry, 0620
Questions:
6
Year:
2021
Paper:
4
Variant:
2
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1
This question is about states of matter. Complete the table, using ticks ( ) and crosses ( ), to describe the properties of gases, liquids and solids. state of matter particles are touching particles have random movement particles are regularly arranged gas liquid solid  Substances can change state. Boiling and evaporation are two ways in which a liquid changes into a gas. Describe two differences between boiling and evaporation.  Name the change of state when: ● a gas becomes a liquid ● a solid becomes a gas.  A substance boils at temperatureX and melts at temperatureY. Complete the graph to show the change in temperature over time as the substance cools from temperatureA to temperatureB. A B Y time X temperature  A solution is a mixture of a solute and a solvent. Name the process when a solid substance mixes with a solvent to form a solution. Name the type of reaction when two solutions react to form an insoluble substance. 
1. States of matter  →  1.1. Solids, liquids and gases
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2
Acids are important laboratory chemicals. Some acids completely dissociate in water to form ions. State the term applied to acids that completely dissociate in water. Complete the equation to show the complete dissociation of sulfuric acid in water. H2SO4 →  State the colour of methyl orange in sulfuricacid. The equation for the reaction between powdered zinccarbonate and dilute nitricacid is shown. ZnCO3 + 2HNO3 → Zn(NO3)2 + H2O + CO2 Complete the equation by adding state symbols. A student found that 2.5 g of zinccarbonate required 20 cm3 of dilute nitricacid to react completely. Calculate the concentration of dilute nitricacid using the following steps: ● calculate the mass of 1mole of ZnCO3  g ● calculate the number of moles of ZnCO3 reacting  moles ● determine the number of moles of HNO3 reacting  moles ● calculate the concentration of HNO3.  mol / dm3  
7. Acids, bases and salts  →  7.1. The characteristic properties of acids and bases
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
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4
Chlorine reacts with carbonmonoxide to produce phosgenegas, COCl 2. A catalyst is used. Cl 2+ COCOCl 2The reaction is exothermic. Explain why the reaction is exothermic in terms of the energy changes of bond breaking and bond making. Complete the energy level diagram for this reaction. On your diagram show: ● the product of the reaction ● an arrow representing the energy change, labelled ∆H ● an arrow representing the activation energy, labelled A. energy progress of reaction Cl 2+ CO State why a catalyst is used. Describe and explain the effect, if any, on the position of equilibrium when: the pressure is increased the temperature is increased. The reaction between chlorine and carbonmonoxide can be represented as shown. Cl Cl Cl + CO C O Cl When one mole of chlorine reacts with one mole of carbonmonoxide, 230 kJ of energy is released. Some bond energies are shown in the table. bond bond energy in kJ / mol Cl –Cl C=O C–Cl Use the information to calculate the energy of the bond between the C and the O in carbonmonoxide, CO.  bond energy in carbon monoxide, CO = kJ / mol Complete the dot-and-cross diagram to show the electron arrangement in a molecule of COCl 2. Cl Cl C O Show outer electrons only. C Cl Cl O  
5. Chemical energetics  →  5.1. Exothermic and endothermic reactions
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5
Iron is a transition element. Potassium is a GroupI element. Iron and potassium have the same type of bonding. Name and describe the type of bonding in these two elements. name description  Transition elements and GroupI elements have some similar physical properties. They can both: ● be hammered into a shape ● conduct electricity ● be stretched into wires. Name the term used to describe the ability of elements to be hammered into a shape. Describe what happens to the particles in iron when it is hammered into a shape. Suggest why copper, rather than other transition elements, is used for wires which conduct electricity. Transition elements are harder and stronger than GroupI elements. Describe how two other physical properties of transition elements are different from those of GroupI elements.  Chemical properties of some GroupI elements are shown in the table. element reaction with cold water reaction with oxygen flame test colour lithium ● steadily effervesces ● forms a colourless solution very slowly forms an oxide layer red sodium ● strongly effervesces ● forms a colourless solution slowly forms an oxide layer potassium ● very strongly effervesces ● forms a colourless solution quickly forms an oxide layer rubidium ruby red Add to the table: ● the flame test colours for sodium and potassium ● the predicted reactions of rubidium with water and with oxygen.  Name the gas produced when GroupI elements react with water. Name the solution formed when potassium reacts with water. Predict the pH of the colourless solution formed when potassium reacts with water. Write the chemical equation for the reaction of sodium with oxygen. Iron is a typical transition element. It is the catalyst used in the Haber process. Write the equation for the reaction that occurs in the Haber process. State the temperature and pressure used in the Haber process. Include units. temperature pressure  
8. The Periodic Table  →  8.4. Transition elements
9. Metals  →  9.1. Properties of metals
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6
Ethanol, C2H5OH, belongs to the homologous series called alcohols. Write the general formula of alcohols. Explain why ethanol cannot be described as a hydrocarbon. Ethanol can be manufactured from different substances by reaction with steam or by fermentation. Give the formula of the substance which reacts with steam to form ethanol. Name a substance which will undergo fermentation to form ethanol. Ethanol is a fuel. Write the chemical equation for the complete combustion of ethanol. Ethane-1,2-diol has two alcohol functional groups. O C H H H C H H H O One molecule of ethane-1,2-diol will react with two molecules of ethanoic acid to form moleculeX. X has two ester functional groups and a molecular formula of C6H10O4. State the empirical formula of X. Draw the structure of X. Show all of the atoms and all of the bonds.  Name the other substance formed in this reaction. Each alcohol functional group in ethane-1,2-diol reacts with acidified potassiummanganate(to form a different organic compound, Y. Name the functional groups formed in Y. Draw the structure of Y. Show all of the atoms and all of the bonds.  
11. Organic chemistry  →  11.6. Alcohols
11. Organic chemistry  →  11.2. Naming organic compounds
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