1. Tutorial on Molarity, Concentration, Standard Solution and Serial Dilution Preparation .Prepared by Lawrence Kok http://lawrencekok.blogspot.com

2. Concentration and Molarity+SoluteSolventmeasuredGramsSolutionmeasuredMolescm3dm3 3. Concentration and Molarity+SoluteSolventConcentrationSolutionmeasured measuredGramsmeasuredMolescm3Conc in mol/dm3 dm3Conc in g/dm3Moles solute in mol Vol of solution in dm3Molarity in MMass solute in grams Vol of solution in dm3 4. Concentration and Molarity+SoluteSolventConcentrationSolutionmeasured measuredGramsmeasuredMolescm3Conc in mol/dm3Conc in g/dm3dm3Moles solute in mol Vol of solution in dm3Mass solute in grams Vol of solution in dm3Find conc in g/dm3 and mol/dm3 46 g NaOH in 1.00dm31 dm3Molarity in M46 g Video on conc/molarity Conc in g/dm3= mass (g) vol dm3 = 46g 1dm3 = 46g/dm3= moles (mol) vol dm3 = 1 mol 1dm3 = 1 mol/dm3 =1MConversion formulaConc in mol/dm3 Moles = massM = 46g 46g/mol = 1 molg/dm3 mol/dm3 g/dm3 M mol/dm3 46g/dm3 46 = 1 mol/dm3 5. Standard solution Preparing standard solution of conc - 1 M NaOH (known accurate concentration)1 M 1 mole NaOH in 1 L/dm346 gStep 1Mass of NaOH 1 mole NaOH x M = 1 x 46gStep 2Transfer to beaker, add water to dissolve itStep 3Transfer from beaker to 1L volumetric flask using filter funnelStep 4Add water until 1L mark with wash bottleStep 5Mix till it dissolved 1M NaOH 1 mole of NaOH in total vol of solution (1000ml) 1M NaOH 6. Standard solution Preparing standard solution of conc - 1 M NaOH (known accurate concentration)1 M 1 mole NaOH in 1 L/dm346 gStep 1Mass of NaOH 1 mole NaOH x M = 1 x 46gStep 2Transfer to beaker, add water to dissolve itStep 3Transfer from beaker to 1L volumetric flask using filter funnelStep 4Add water until 1L mark with wash bottleStep 5Mix till it dissolved 1M NaOH 1 mole of NaOH in total vol of solution (1000ml) 1M NaOHMolarity = 1 mole (1M) 1 L total solution vol (solute + solvent)Molarity = 1 mole (1M) 1 L of vol solvent 7. Standard solutionSolution of known concentrationPreparing standard solution of conc - 1 M NaOH1 M 1 mole NaOH in 1 L/dm346 gStep 1Mass of NaOH 1 mole NaOH x M = 1 x 46gStep 2Transfer to beaker, add water to dissolve itStep 3Transfer from beaker to 1L volumetric flask using filter funnelStep 4Add water until 1L mark with wash bottleStep 5Mix till it dissolved 1M NaOH 1 mole of NaOH in total vol of solution (1000ml) 1M NaOHMolarity = 1 mole (1M) 1 L total solution vol (solute + solvent)Molarity = 1 mole (1M) 1 L of vol solventVideo standard solution preparation 8. Diluting a standard solution1 dm3Adding water1 dm3Dilution Solute 5 moles+Solvent 1 L/dm3Conc Solution 5M or 5 mol/dm3Diluted solution 2.5M or 2.5 mol/dm3 9. Diluting a standard solutionAdding water1 dm31 dm3Dilution Solute 5 moles+Solvent 1 L/dm3Conc Solution 5M or 5 mol/dm3Diluted solution 2.5M or 2.5 mol/dm3Dilution 1 NaOH5 moles NaOH in 1 dm3 5 M or 5mol/dm30.5NaOH5 moles NaOH in 2 dm3 2.5 M or 2.5mol/dm31 dm3Moles bef dilution = 5 mol Vol bef = 1 dm3 Conc = 5M1 dm3Moles after dilution = 5 mol Vol after = 2 dm3 Conc = 2.5MVol Increase , Conc decrease Number mole NO CHANGE 10. Diluting a standard solutionAdding water1 dm31 dm3Dilution Solute 5 moles+Solvent 1 L/dm3Conc Solution 5M or 5 mol/dm3Diluted solution 2.5M or 2.5 mol/dm3Dilution 1 NaOH5 moles NaOH in 1 dm3 5 M or 5mol/dm30.5NaOH1 dm35 moles NaOH in 2 dm3 2.5 M or 2.5mol/dm31 dm3Moles bef dilution = 5 mol Vol bef = 1 dm3 Conc = 5MMoles after dilution = 5 mol Vol after = 2 dm3 Conc = 2.5MMoles = Molarity(M) x Vol (dm3) =MxV Before =5x1 = 5 molesVol Increase , Conc decrease Number mole NO CHANGEMoles = Molarity(M) x Vol (dm3) =MxV After = 2.5 x 2 = 5 molesMoles before dilution = Moles after dilutionM1 V1 = M2V2M1 = Initial molarity M2 = Final molarity V1 = Initial volume V2 = Final volumeM1 V1 = M2V2 11. Diluting a standard solution (1M) (0.1M) 1 M 1 mole NaOH in 1 dm3 (stock solution)Standard solution , molarity - 1 M NaOHStep 1 Step 2Pipette 10cm3 of 1M NaOH with a pipetteStep 3Transfer 10cm3 to a volumetric flaskStep 4Add 90 cm3 water, to a total vol of 100cm3Step 510cm31M NaOH in a volumetric flaskMix to dissolve, 0.1M NaOH10cm390cm31M0.1M 12. Diluting a standard solution (1M) (0.1M) 1 M 1 mole NaOH in 1 dm3 (stock solution)Standard solution , molarity - 1 M NaOHStep 1 Step 2Pipette 10cm3 of 1M NaOH with a pipetteStep 3Transfer 10cm3 to a volumetric flaskStep 4Add 90 cm3 water, to a total vol of 100cm3Step 510cm31M NaOH in a volumetric flaskMix to dissolve, 0.1M NaOH10cm390cm31M0.1MMoles before dilution = Moles after dilutionM1 V1 = M2V2M1 = Initial molarity M2 = Final molarity V1 = Initial volume V2 = Final volume3M1 V1 = M2V21M x 10cm = 0.1M x 100cm3 (10 + 90) 1000 1000 13. Diluting a standard solution (1M) (0.1M) 1 M 1 mole NaOH in 1 dm3 (stock solution)Standard solution , molarity - 1 M NaOHStep 1 Step 2Pipette 10cm3 of 1M NaOH with a pipetteStep 3Transfer 10cm3 to a volumetric flaskStep 4Add 90 cm3 water, to a total vol of 100cm3Step 510cm31M NaOH in a volumetric flaskMix to dissolve, 0.1M NaOH10cm390cm31M0.1MMoles before dilution = Moles after dilutionM1 V1 = M2V2M1 = Initial molarity M2 = Final molarity V1 = Initial volume V2 = Final volume3M1 V1 = M2V21M x 10cm = 0.1M x 100cm3 (10 + 90) 1000 1000Video standard solution preparation 14. Diluting a standard solutionSerial DilutionDilution Start with Conc solution (stock) Add water to dilute it down Difficult to cover a wide range Time consuming to perform different dilution for different concentrationSerial dilutionVs Easier to make, cover a wide range of conc Same dilution over again Using previous dilution in next step 1 in 10 serial dil - 1 part stock 9 part water - (10x dil), (10 fold), (1 : 10) 1 in 2 serial dil 1 part stock 1 part water - (2x dil), (2 fold), (1 : 2) 15. Diluting a standard solutionSerial DilutionDilution Start with Conc solution (stock) Add water to dilute it down Difficult to cover a wide range Time consuming to perform different dilution for different concentrationSerial dilutionVsStock solution 1M NaOH Easier to make, cover a wide range of conc Same dilution over again Using previous dilution in next step 1 in 10 serial dil - 1 part stock 9 part water - (10x dil), (10 fold), (1 : 10) 1 in 2 serial dil 1 part stock 1 part water - (2x dil), (2 fold), (1 : 2)Prepare 0.1M NaOHPrepare a 10 x fold serial dil 1M NaOH Tube 21 cm31 cm3Tube 31 cm3Tube 11 cm3Tube 41 cm39 cm3 9 cm39 cm39 cm39 cm3 16. Diluting a standard solutionSerial DilutionDilutionSerial dilution Start with Conc solution (stock) Add water to dilute it down Difficult to cover a wide range Time consuming to perform different dilution for different concentrationVsStock solution 1M NaOH Easier to make, cover a wide range of conc Same dilution over again Using previous dilution in next step 1 in 10 serial dil - 1 part stock 9 part water - (10x dil), (10 fold), (1 : 10) 1 in 2 serial dil 1 part stock 1 part water - (2x dil), (2 fold), (1 : 2)Prepare 0.1M NaOHPrepare a 10 x fold serial dil 1M NaOH Tube 21 cm31 cm3Tube 31 cm3Tube 11 cm3Tube 41 cm39 cm3 9 cm3 Step 1Pipette 9cm3 water to tube 1Step 2Pipette 1 cm3 stock to tube 19 cm39 cm39 cm3Step 1Dilution 1M 0.1MDilution factor = 1o parts (9 part water +1 part solute) (10x, 1:10) 1 part (1 part solute)Pipette 1 cm3 stock to tube 1+Mix wellStep 3Pipette 1 cm3 from tube 1 to 2Mix wellPipette 1 cm3 from tube 2 to 3+ +Step 5Mix wellStep 2Step 4+Pipette 9cm3 water to tube 1, 2, 3, 4Pipette 1 cm3 from tube 3 to 4+Mix wellMix wellSerial dil 10 fold 1M 0.1M, 0.01M, 0.001M, 0.0001M 17. Dilution factor = 1o parts (5 part water +5 part solute) (2x, 1:2) 5 parts (5 part solute)Serial DilutionDilution factor = 1o parts (9 part water +1 part solute) (10x, 1:10) 1 part (1 part solute)Stock solution 1M NaOH Prepare 2x fold serial dil 1M NaOH Tube 4Tube 3Tube 2Prepare 10x fold serial dil 1M NaOH5 cm3 5 cm35 cm35 cm35 cm35 cm3Tube 1Tube 1Tube 31 cm31 cm3Tube 41 cm35 cm35 cm3Tube 29 cm39 cm31 cm39 cm39 cm3 18. Dilution factor = 1o parts (5 part water +5 part solute) (2x, 1:2) 5 parts (5 part solute)Serial DilutionDilution factor = 1o parts (9 part water +1 part solute) (10x, 1:10) 1 part (1 part solute)Stock solution 1M NaOH Prepare 2x fold serial dil 1M NaOH Tube 4Tube 3Tube 2Prepare 10x fold serial dil 1M NaOH Tube 15 cm35 cm35 cm35 cm35 cm35 cm39 cm3Pipette 5cm3 water to tube 1, 2, 3, 4Tube 31 cm3Tube 41 cm35 cm3 5 cm3Tube 21 cm3Tube 1Step 19 cm31 cm39 cm39 cm3Pipette 9cm3 water to tube 1, 2, 3, 4Pipette 5cm3 stock to tube 1+Mix wellStep 2Pipette 1cm3 stock to tube 1+Mix wellPipette 5cm3 from tube 1 to 2+Mix wellStep 3Pipette 1cm3 from tube 1 to 2+Mix wellPipette 5cm3 from tube 2 to 3+Mix wellStep 4Pipette 1cm3 from tube 2 to 3+Mix wellPipette 5cm3 from tube 3 to 4+Mix wellStep 5Pipette 1cm3 from tube 3 to 4+Mix wellSerial dil 2 fold 1M 0.5M, 0.25M, 0.125M, 0.0625MSerial dil 10 fold 1M 0.1M, 0.01M, 0.001M, 0.0001M 19. Dilution factor = 1o parts (5 part water +5 part solute) (2x, 1:2) 5 parts (5 part solute)Serial DilutionDilution factor = 1o parts (9 part water +1 part solute) (10x, 1:10) 1 part (1 part solute)Stock solution 1M NaOH Prepare 2x fold serial dil 1M NaOH Tube 4Tube 3Tube 2Prepare 10x fold serial dil 1M NaOH Tube 15 cm35 cm35 cm35 cm35 cm35 cm39 cm3Pipette 5cm3 water to tube 1, 2, 3, 4Tube 3Tube 41 cm31 cm35 cm3 5 cm3Tube 21 cm3Tube 1Step 19 cm31 cm39 cm39 cm3Pipette 9cm3 water to tube 1, 2, 3, 4Pipette 5cm3 stock to tube 1+Mix wellStep 2Pipette 1cm3 stock to tube 1+Mix wellPipette 5cm3 from tube 1 to 2+Mix wellStep 3Pipette 1cm3 from tube 1 to 2+Mix wellPipette 5cm3 from tube 2 to 3+Mix wellStep 4Pipette 1cm3 from tube 2 to 3+Mix wellPipette 5cm3 from tube 3 to 4+Mix wellStep 5Pipette 1cm3 from tube 3 to 4+Mix wellSerial dil 2 fold 1M 0.5M, 0.25M, 0.125M, 0.0625M Animation serial dilutionSerial dil 10 fold 1M 0.1M, 0.01M, 0.001M, 0.0001M Video serial dilution 20. Serial Dilution Stock solution 1M NaOH Prepare 2x fold serial dil 1M NaOH Tube 4Tube 3Tube 2Prepare 10x fold serial dil 1M NaOH5 cm3 5 cm35 cm35 cm3 X1 165 cm3 X1 8Tube 1Tube 1Tube 2X1 41 cm35 cm3 X1 2Dilution factorDilution factor = 1o parts (5 part water +5 part solute) (2x, 1:2) 5 part (5 part solute)Tube 41 cm35 cm35 cm3Tube 39 cm3X1 101 cm39 cm3X1 1001 cm39 cm3X1 10009 cm3X1 10000Dilution factorDilution factor = 1o parts (9 part water +1 part solute) (10x, 1:10) 1 part (1 part solute) 21. Serial Dilution Stock solution 1M NaOH Prepare 2x fold serial dil 1M NaOH Tube 4Tube 3Tube 2Prepare 10x fold serial dil 1M NaOH Tube 1Tube 15 cm35 cm3 X1 165 cm3 X1 85 cm35 cm3 X1 4Tube 31 cm35 cm3 XTube 41 cm35 cm3 5 cm3Tube 29 cm31 2XDilution factor1 101 cm39 cm3X1 1001 cm39 cm3X1 10009 cm3X1 10000Dilution factorDilution factor = 1o parts (9 part water +1 part solute) (10x, 1:10) 1 part (1 part solute)Dilution factor = 1o parts (5 part water +5 part solute) (2x, 1:2) 5 part (5 part solute)Pipette 5cm3 water to tube 1, 2, 3, 4Step 1Pipette 9cm3 water to tube 1, 2, 3, 4Pipette 5cm3 stock to tube 1+Mix wellStep 2Pipette 1cm3 stock to tube 1+Mix wellPipette 5cm3 from tube 1 to 2+Mix wellStep 3Pipette 1cm3 from tube 1 to 2+Mix wellPipette 5cm3 from tube 2 to 3+Mix wellStep 4Pipette 1cm3 from tube 2 to 3+Mix wellPipette 5cm3 from tube 3 to 4+Mix wellStep 5Pipette 1cm3 from tube 3 to 4+Mix well 22. Serial Dilution Stock solution 1M NaOH Prepare 2x fold serial dil 1M NaOH Tube 4Tube 3Tube 2Prepare 10x fold serial dil 1M NaOH Tube 1Tube 15 cm35 cm3 X1 165 cm3 X1 85 cm35 cm3 X1 4Tube 31 cm35 cm3 XTube 41 cm35 cm3 5 cm3Tube 29 cm31 2XDilution factor1 101 cm39 cm3X1 1001 cm39 cm3X1 10009 cm3X1 10000Dilution factorDilution factor = 1o parts (9 part water +1 part solute) (10x, 1:10) 1 part (1 part solute)Dilution factor = 1o parts (5 part water +5 part solute) (2x, 1:2) 5 part (5 part solute)Pipette 5cm3 water to tube 1, 2, 3, 4Step 1Pipette 9cm3 water to tube 1, 2, 3, 4Pipette 5cm3 stock to tube 1+Mix wellStep 2Pipette 1cm3 stock to tube 1+Mix wellPipette 5cm3 from tube 1 to 2+Mix wellStep 3Pipette 1cm3 from tube 1 to 2+Mix wellPipette 5cm3 from tube 2 to 3+Mix wellStep 4Pipette 1cm3 from tube 2 to 3+Mix wellPipette 5cm3 from tube 3 to 4+Mix wellStep 5Pipette 1cm3 from tube 3 to 4+Mix wellSerial dil 2 fold 1M 0.5M, 0.25M, 0.125M, 0.0625MSerial dil 10 fold 1M 0.1M, 0.01M, 0.001M, 0.0001M 23. Concept Map Moles = Mass Molar mass 1 mole gasMole = Vol gas (stp) 22.4Moles = M(Molarity) x V(Vol) 24. Concept Map Moles = Mass Molar mass 1 mole gasMole = Vol gas (stp) 22.4Moles in solution = M x V M = Molarity -M or mol/dm3 V = Vol in dm3mole changes Moles in solution = M x V1000 Moles = M(Molarity) x V(Vol)M = Molarity- M or mol/dm3 V = Vol in cm3 25. Concept Map Moles = Mass Molar mass 1 mole gasMole = Vol gas (stp) 22.4Moles in solution = M x V M = Molarity -M or mol/dm3 V = Vol in dm3mole changes Moles bef dilution = Moles aft dilutionM1 V1 = M2V2M1 = Ini molarity M2= Final molarity V1 = Initial vol V2 = Final volMoles in solution = M x V1000 Moles = M(Molarity) x V(Vol) mole NO change concentration changeM = Molarity- M or mol/dm3 V = Vol in cm3 26. Moles vs Concentration/Molarity 1 dm3 1 dm3 1 dm3 5 molesMolarity = 5M Moles bef dilution = Moles aft dilutionM1 V1 = M2V2M1 = Ini molarity M2= Final molarity V1 = Initial vol V2 = Final vol1 dm32 dm3Moles = M x V = 5M x 1 dm3 = 5 mol 27. Moles vs Concentration/Molarity 1 dm3 1 dm3 1 dm3 5 molesMolarity = 5M Moles bef dilution = Moles aft dilutionM1 V1 = M2V2M1 = Ini molarity M2= Final molarity V1 = Initial vol V2 = Final vol1 dm3Moles = M x V = 5M x 1 dm3 = 5 mol2 dm3Moles bef dilution = Moles aft dilution Conc = 5MM1 V1 = M2V2 5 x 1 = M2 x 2 M2 = 5/2 M2 = 2.5MMoles = M x V = 5M x 1 dm3 = 5 molconcentration Conc = 2.5MMole = M x V = 2.5M x 2dm3 = 5 molchangemole NO change 28. Moles vs Concentration/Molarity 1 dm3 1 dm3 1 dm31 dm3 Molarity = 5M1 dm3 5 molesMolarity = 5M Moles bef dilution = Moles aft dilutionM1 V1 = M2V2M1 = Ini molarity M2= Final molarity V1 = Initial vol V2 = Final volMoles = M x V = 5M x 1 dm3 = 5 mol1 dm31 dm32 dm3Moles bef dilution = Moles aft dilution Conc = 5MM1 V1 = M2V2 5 x 1 = M2 x 2 M2 = 5/2 M2 = 2.5MMoles = M x V = 5M x 1 dm3 = 5 molconcentration Conc = 2.5MMole = M x V = 2.5M x 2dm3 = 5 molchangemole NO change2 dm3 29. Moles vs Concentration/Molarity 1 dm3 1 dm3 1 dm31 dm3 Molarity = 5M1 dm3 5 molesMolarity = 5M Moles bef dilution = Moles aft dilutionM1 V1 = M2V2M1 = Ini molarity M2= Final molarity V1 = Initial vol V2 = Final volMoles = M x V = 5M x 1 dm3 = 5 mol1 dm31 dm3Mole = M x V = 5M x 1dm3 = 5 mol2 dm32 dm3 Mole = M x V = 5M x 2dm3 = 10 molmole changeMole = M x V Conc = Mole V = 10mol 2dm3 Conc = 5MConcentration NO changeMoles bef dilution = Moles aft dilution Conc = 5MM1 V1 = M2V2 5 x 1 = M2 x 2 M2 = 5/2 M2 = 2.5MMoles = M x V = 5M x 1 dm3 = 5 molconcentration Conc = 2.5MMole = M x V = 2.5M x 2dm3 = 5 molchangemole NO changeMole = M x V Conc = Mole V = 5mol 1dm3 Conc = 5M 30. Moles vs Concentration/Molarity 1 dm3 1 dm3 1 dm3 5 molesMolarity = 5M Moles bef dilution = Moles aft dilutionM1 V1 = M2V2M1 = Ini molarity M2= Final molarity V1 = Initial vol V2 = Final vol1 dm32 dm3Moles = M x V = 5M x 1 dm3 = 5 mol 31. Moles vs Concentration/Molarity 1 dm3 1 dm3 1 dm3 5 molesMolarity = 5M Moles bef dilution = Moles aft dilutionM1 V1 = M2V2M1 = Ini molarity M2= Final molarity V1 = Initial vol V2 = Final vol1 dm3Moles = M x V = 5M x 1 dm3 = 5 mol2 dm3Moles bef dilution = Moles aft dilution Conc = 5MM1 V1 = M2V2 5 x 1 = M2 x 2 M2 = 5/2 M2 = 2.5MMoles = M x V = 5M x 1 dm3 = 5 molconcentration Conc = 2.5MMole = M x V = 2.5M x 2dm3 = 5 molchangemole NO change 32. Moles vs Concentration/Molarity 1 dm3 1 dm3 1 dm1 dm331 dm3 5 molesMolarity = 10MMolarity = 5M Total = 5 + 10 = 15 mol molesMoles bef dilution = Moles aft dilutionM1 V1 = M2V2M1 = Ini molarity M2= Final molarity V1 = Initial vol V2 = Final volMoles = M x V = 5M x 1 dm3 = 5 mol1 dm31 dm32 dm3Moles bef dilution = Moles aft dilution Conc = 5MM1 V1 = M2V2 5 x 1 = M2 x 2 M2 = 5/2 M2 = 2.5MMoles = M x V = 5M x 1 dm3 = 5 molconcentration Conc = 2.5MMole = M x V = 2.5M x 2dm3 = 5 molchangemole NO change2 dm3 33. Moles vs Concentration/Molarity 1 dm3 1 dm3 1 dm1 dm331 dm3 5 molesMolarity = 10MMolarity = 5M Total = 5 + 10 = 15 mol molesMoles bef dilution = Moles aft dilutionM1 V1 = M2V2M1 = Ini molarity M2= Final molarity V1 = Initial vol V2 = Final volMoles = M x V = 5M x 1 dm3 = 5 mol1 dm31 dm3Mole = M x V = 5M x 1 dm3 = 5 mol2 dm32 dm3 Mole = M x V = 7.5M x 2dm3 = 15 molmole changeMole = M x V Conc = Mole V = 15mol 2dm3 = 7.5MConcentration changeMoles bef dilution = Moles aft dilution Conc = 5MM1 V1 = M2V2 5 x 1 = M2 x 2 M2 = 5/2 M2 = 2.5MMoles = M x V = 5M x 1 dm3 = 5 molconcentration Conc = 2.5MMole = M x V = 2.5M x 2dm3 = 5 molchangemole NO changeMole = M x V Conc = Mole V = 5mol 1dm3 = 5M 34. IB Questions on Conc and Molarity 135.00g of copper(II) sulphate dissolve in water form 500cm3 solution. Cal conc in g/dm3 and mol/dm3Cal vol in dm3 of 0.8M H2SO4 which contain 0.2 mol.2Cal mass of Na2CO3 require to dissolve in water to prepare 200cm3 solution, containing 50 g/dm34Cal moles of NH3 in 150cm3 of 2M aqueous NH3 solution. 35. IB Questions on Conc and Molarity 15.00g of copper(II) sulphate dissolve in water form 500cm3 solution. Cal conc in g/dm3 and mol/dm32Cal mass of Na2CO3 require to dissolve in water to prepare 200cm3 solution, containing 50 g/dm3 Answer: Vol = 200cm3 0.2dm3Answer: Mass copper(II) sulphate = 5.00g Vol solution = 500cm3 500/1000 0.5dm3 Conc = Mass Vol 5.00g 0.5dm3 = 5.00g 0.5dm3 = 10.0g/dm3 Alternative 0.5dm3 5.00g 5.00 g 1 dm3 5.00 x 1 0.5 = 10g/dm3 0.5 dm3Conc (g/dm3) = mass(g) vol(dm3) Mass = conc(g/dm3) x vol(dm3) = 50 x 0.2 = 10g Alternative 1 dm3 50g 0.2dm3 50 x 0.2 = 10g10g0.2 dm3Convert g/dm3 to mol/dm3 RMM copper(II) sulphate = 160 mol/dm3 g/dm3 RMM = 10 160 = 0.0625M 3Cal vol in dm3 of 0.8M H2SO4 which contain 0.2 mol. Answer: Moles = M x V V = mol M V = 0.2 mol 0.8mol/dm3 V = 0.25dm30.2mol0.8M4Cal moles of NH3 in 150cm3 of 2M aqueous NH3 solution. Answer: Moles = M x V 1000 = 2 X 150 1000 = 0.3 mol2M 150cm3 36. IB Questions on Conc and Molarity 54.0g of Na2CO3 dissolved in water, making up 250cm3 Calculate its molarity.678Cal moles of hydrogen ions H+ in 200cm3 of 0.5M H2SO4250cm3 of HNO3 contain 0.4moles. Cal its molarity.HCI acid has conc of 2.0M. Cal the mass of hydrogen chloride gas in 250cm3 in HCI. 37. IB Questions on Conc and Molarity 54.0g of Na2CO3 dissolved in water, making up 250cm3 Calculate its molarity. Answer: Moles Na2CO3 = Mass M = 16 106 = 0.0377 mol Moles = M x V 0.0377 = M x 0.25 M = 0.0377 0.25 M = 0.15M Alternative Conc in g/dm3 = Mass Vol = 4g 0.25dm3 = 16g/dm3 3 to mol/dm3 Convert g/dm mol/dm3 g/dm3 RMM = 16 106 = 0.15M80.0377mol0.25 dm37RMM = 106H2SO4 2 H+ + SO42-Moles?0.5M 0.2 dm3H2SO4 diprotic produce 2 mol H+ ions Moles H+ = 2 x 0.1 mol = 0.2 mol250cm3 of HNO3 contain 0.4moles. Cal its molarity. Answer: 0.4mol Moles = M x V 1000 0.4 = M X 250 1000 M = 0.4 x 1000 250 = 1.6M 0.25 dm3 Alternative 0.25 dm3 0.4 mol HNO3 1 dm3 0.4 x 1 mol HNO3 0.25 = 1.6M250cm 3 0.25dm3Cal moles of hydrogen ions H+ in 200cm3 of 0.5M H2SO4 Answer: Moles = M x V 1000 = 0.5 X 200 1000 = 0.1 mol6HCI acid has conc of 2.0M. Cal the mass of hydrogen chloride gas in 250cm3 in HCI. Mass ? Answer: Moles = M x V 1000 = 2.0 X 250 1000 2.0M = 0.5 mol 0.25 dm3 RMM HCI= 36.5 Mass of HCI = Moles x RMM = o.5 x 36.5 = 18.25g 38. IB Questions on Conc and Molarity 911Cal molarity of KOH when 750cm3 water added to 250cm3, 0.8M KOHCal molarity of NaOH produce when 500cm3 , 2mol NaOH added to 1500cm3, 4mol NaOH1012Cal vol of water added to 60cm3, 2.0M of H2SO4 to produce 0.3M H2SO4Cal molarity of HCI produce when 200cm3 , 2M HCI added to 300cm3, 0.5M of HCI 39. IB Questions on Conc and Molarity 9Cal molarity of KOH when 750cm3 water added to 250cm3, 0.8M KOH10Cal vol of water added to 60cm3, 2.0M of H2SO4 to produce 0.3M H2SO4 AnswerAnswer 250cm1000cm33750cm30.8MM1 V1 = M2V2M1 V1 = M2V22.0 x 60 = 0.3 x V2 V2 = 2.0 x 60 0.3 V2 = 400cm3 (final vol) Vol water = 400 60 = 340cm3 added0.8 x 250 = M2 x 1000 M2 = 0.8 x 250 Final vol 1000 750 + 250 = 1000cm3 M2 = 0.2M Cal molarity of NaOH produce when 500cm3 , 2mol NaOH added to 1500cm3, 4mol NaOH12Cal molarity of HCI produce when 200cm3 , 2M HCI added to 300cm3, 0.5M of HCI AnswerAnswerA2 mol+6 mol4 mol2M 200cm3500cm0.3MMoles bef dilution = Moles aft dilutionMoles bef dilution = Moles aft dilution11? cm360cm3 2M31500cmB+0.5M 300cm3C ?M 500cm33Total moles = (2.0 + 4.0) = 6mol Total vol = (500 + 1500) = 2000cm3 2dm3 Moles = M x V M = Moles V = 6 mol 2 dm3 = 3.0 mol/dm32000cm3Mole = M x V A 1000 = 2.0 x 200 = 0.4mol 1000 Total moles A + B = 0.4 + 0.15 = 0.55 mol Total vol = (200 + 300) = 500cm3 0.5dm3 Moles = M x V M = Moles = 0.55 = 1.1M V 0.5Mole = M x V B 1000 = 0.5 x 300 = 0.15mol 1000 40. IB Questions on Conc and Molarity 1315Prepare 250cm3, 0.1M HCI using concentrated HCI, 1.63M. What vol of concentrated acid must be diluted.How to prepare 500cm3 of 0.1M NaCI solution ?14Cal conc formed when 2.00g KCI dissolved in 250cm3 of solution16How to prepare 1.2dm3 of 0.4M HCI solution starting from 2.0M HCI ? 41. IB Questions on Conc and Molarity 13Prepare 250cm3, 0.1M HCI using concentrated HCI, 1.63M. What vol of concentrated acid must be diluted.14Answer? cm3Answer 1.63M2.00g0.1M250cm3250cm3Moles KCI = mass (solid) M = 2.00 = 0.02683 mol 74.55 Moles KCI = M x V 250 cm3 0.250dm3 (solution) M = moles = 0.02683 V 0.250 M = 0.107 mol/dm3Moles bef dilution = Moles aft dilutionM1 V1 = M2V2Moles aft dilution = M x V 250 cm3 0.250dm3 = 0.1 x 0.25 = 0.025mol Moles bef dilution = 0.025 M x V = 0.025 V = 0.025 = 0.025 = 0.0154 dm3 or 15.4 cm3 M 1.63 15How to prepare 500cm3 of 0.1M NaCI solution ? AnswerCal conc formed when 2.00g KCI dissolved in 250cm3 of solution16How to prepare 1.2dm3 of 0.4M HCI solution starting from 2.0M HCI ? Answer2..92g NaCI 0.1 M240 cm3 0.4 M2M500cm3 500 cm 0.5dm Moles NaCI = M x V 3 = 0.1 x 0.5dm = 0.05 mol needed Moles NaCI = Mass RMM Mass = Moles x RMM = 0.05 x 58.5 = 2.92g 31.2 dm3 3Weigh 2.92g of NaCI (0.05mol) and make up to 500cm3 solution in a 500cm3 volumetric flaskMoles of HCI = M x V = 0.4 x 1.2 = 0.48 mol Moles bef dilution = Moles aft dilutionM1 V1 = M2V2 2 x V1 = 0.4 x 1.2 V1 = 0.4 x 1.2 2cm33 3 V = 0.24 dm or 240 cmMeasure 240 of 2M HCI and make up to 1.2 dm3 with water using volumetric flask 42. Acknowledgements Thanks to source of pictures and video used in this presentation Thanks to Creative Commons for excellent contribution on licenses http://creativecommons.org/licenses/Prepared by Lawrence Kok Check out more video tutorials from my site and hope you enjoy this tutorial http://lawrencekok.blogspot.com