7. Acids, bases and salts
A section of Chemistry, 0620
Listing 10 of 506 questions
Silver bromide, AgBr, is made when aqueous silver ethanoate, CH3COOAg, is added to aqueous sodium bromide, NaBr. The equation for the reaction is shown in equation 1. equation 1 CH3COOAg + NaBr → CH3COONa + AgBr The method includes the following steps. step 1 Add 200.0 cm3 of 0.0500 mol / dm3 CH3COOAg to a beaker. This volume contains 0.0100 mol of Ag+ ions. step 2 Add 50.0 cm3 of aqueous NaBr. This volume contains 0.0100 mol of Br – ions. A precipitate forms. step 3 Filter the mixture. step 4 Dry the solid residue until all the water is removed. step 5 Record the mass of the dry residue. Complete the ionic equation for the reaction by adding the missing state symbols. Ag+( ) + Br –( ) → AgBr( ) Name a different aqueous silver salt which could be used in step 1. Use the information in step 2 to calculate the concentration of aqueous NaBr. concentration = mol / dm3 State the colour of the precipitate which forms in step 2. Use the information in step 1, step 2 and equation 1 to determine the number of moles of AgBr formed. Use this value to calculate the mass of AgBr formed. number of moles of AgBr = mass of AgBr = g Name the salt dissolved in the filtrate in step 3. The recorded mass of the dry residue in step 5 is greater than the mass calculated in because a step is missing from the procedure. Suggest the missing step. Name the substance responsible for the greater mass of the dry residue. Barium sulfate can be made by the same method but with different aqueous solutions. Suggest two aqueous solutions which can be added together to make barium sulfate. and Write the balanced symbol equation for this reaction.
0620_w24_qp_42
THEORY
2024
Paper 4, Variant 2
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