7.1. The characteristic properties of acids and bases
A subsection of Chemistry, 0620, through 7. Acids, bases and salts
Listing 10 of 260 questions
Ethanoic acid is a weak acid and hydrochloric acid is a strong acid. Both ethanoic acid and hydrochloric acid dissociate in aqueous solution. Define the term acid. The chemical equation shows the changes which occur when the strong acid, hydrochloricacid, is added to water. HCl H++ Cl –Complete the chemical equation to show the changes which occur when the weak acid, ethanoicacid, is added to water. CH3COOHA student does experiments to show that hydrochloricacid is a strong acid and ethanoicacid is a weak acid. The student adds an excess of hydrochloricacid and an excess of ethanoicacid to separate samples of lumps of calciumcarbonate. Only the identity of the acid is changed between the experiments. All other conditions are kept the same. State two observations which would show that hydrochloricacid is a stronger acid than ethanoicacid.  The student uses the same size container and checks that the pressure is the same for each experiment. State three other conditions which must be kept the same to ensure fair testing.  Hydrochloric acid produces salts called chlorides. Magnesium carbonate reacts with hydrochloric acid to produce magnesiumchloride. MgCO3 + 2HCl MgCl 2 + H2O + CO2 A student used 50.00 cm3 of 2.00 mol / dm3 hydrochloric acid in an experiment to produce magnesiumchloride. Calculate the mass, in g, of magnesium carbonate needed to react exactly with 50.00 cm3 of 2.00 mol / dm3 hydrochloric acid using the following steps. ● ● Calculate the number of moles of HCl present in 50.00 cm3 of 2.00 mol / dm3 HCl.  mol ● ● Determine the number of moles of MgCO3 which would react with 50.00 cm3 of 2.00 mol / dm3HCl.  mol ● ● Calculate the relative formula mass, Mr, of MgCO3.  Mr of MgCO3 = ● ● Calculate the mass of MgCO3 needed to react exactly with 50.00 cm3 of 2.00 mol / dm3HCl.  mass = g  A student prepares crystals of magnesium chloride by adding an excess of magnesiumcarbonate to 50.00 cm3 of 2.00 mol / dm3 hydrochloricacid. The student filters the mixture and rinses the residue. Why does the student add an excess of magnesium carbonate? Why does the student rinse the residue? Describe how the student would obtain pure crystals of magnesium chloride from the filtrate. Silver chloride, AgCl, is insoluble. It can be made by a precipitation reaction between aqueous bariumchloride and a suitable aqueous silver salt. What is meant by the term precipitate? Name a suitable silver salt to use to prepare silverchloride. Complete the chemical equation to show the formation of insoluble silver chloride from aqueous barium chloride and the silver salt you have named. name of a suitable silver salt BaCl 2 + +  
0620_s19_qp_41
THEORY
2019
Paper 4, Variant 1
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