0620_s24_qp_31
A paper of Chemistry, 0620
Questions:
8
Year:
2024
Paper:
3
Variant:
1

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Table 2.1 shows the percentages by mass of the elements present in the human body. Table 2.1 element percentage by mass of element calcium 1.50 carbon 18.00 chlorine 0.15 hydrogen 10.00 magnesium 0.05 nitrogen 3.00 oxygen 65.00 phosphorus 1.00 potassium 0.35 sodium 0.15 sulfur 0.25 other elements 0.55 Answer these questions using information from Table 2.1. Name the non-metallic element in Table 2.1 that has the lowest percentage by mass. Name an element in Table 2.1 that is in Period 4 of the Periodic Table. Some medicines contain a compound made of Mg2+ ions and OH– ions. Name the compound made of Mg2+ ions and OH– ions. Describe the observations when aqueous sodium hydroxide is added dropwise to a solution containing calcium ions until the sodium hydroxide is in excess. observations with dropwise addition of sodium hydroxide observations with excess sodium hydroxide  Name a calcium salt that is soluble in water. Table 2.2 shows some properties of the Group I metals. Table 2.2 metal melting point / °C observations on reaction with water lithium sodium bubbles form rapidly but no flame potassium bubbles form very rapidly and flame rubidium explodes Use the information in Table 2.2 to predict: ● the melting point of potassium ● the observations when lithium reacts with water.   State how the density of the Group I elements changes down the group. Sodium reacts with water to produce sodium hydroxide and a gas which pops with a lighted splint. Complete the symbol equation for this reaction. Na + 2H2O → 2NaOH +  
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Large pieces of solid sulfur burn in excess oxygen to produce sulfur dioxide gas. Complete the equation by adding the missing state symbol. S( ) + O2→ SO2 shows how the mass of sulfur changes as the reaction proceeds. time / seconds mass of sulfur / g Deduce the time taken for the reaction to finish. The experiment is repeated using powdered sulfur. Describe the effect on the rate of reaction of using powdered sulfur rather than large pieces of sulfur. Sulfur dioxide reacts with oxygen in a closed container. 2SO2+ O22SO3Describe the effect, if any, each of the following has on the rate of this reaction. All other conditions stay the same. ● The temperature is decreased. ● The pressure of the gases is increased.  Changing concentration changes the rate of a reaction. Choose the correct unit of concentration from the list. Draw a circle around your chosen answer. dm3 / mol mol / dm mol / dm2 mol / dm3 Sulfur dioxide is an air pollutant. State one adverse effect of sulfur dioxide. Emissions of sulfur dioxide can be reduced by using low-sulfur fossil fuels. State one other way of reducing sulfur dioxide emissions from fossil fuels. Aqueous sodium hydrogen sulfite releases sulfur dioxide gas at room temperature. Sulfur dioxide changes the colour of acidified potassium manganate(from purple to colourless. shows a sealed tube with a small volume of aqueous sodium hydrogen sulfite at the bottom. A piece of filter paper soaked in acidified potassium manganate(is attached to the top of the tube. filter paper soaked in acidified potassium manganate(aqueous sodium hydrogen sulfite The filter paper remains purple at first. The filter paper becomes colourless after a short time. Explain these results in terms of kinetic particle theory. 
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