1. Problem Solving Tutor Next This presentation is designed to develop your problem solving skills in quantitative chemistry. Working through the whole tutor program you will develop and use three techniques for problem solving. These have been called: 1. Knowing what you know (do this one first) 2. Tabulating the information (do this one second) 3. Storyboarding (do this one last) You are about to start: Tabulating the information

2. Some important points: You will need to use a calculator (or the calculator function on your computer/device). Do not use the keyboard to advance or go back through slides. Use the mouse/screen tap and the icons: NextBack Next

3. Problem solving tutor Tabulating the information Tabulating the information is an analysis skill that, once learned, you will be able to apply on paper to solve complex questions. It enables you to start the question even if you cannot see how to tackle the calculation straight away. Next

4. There are two questions to work through in the training for this problem solving skill. Question 2 is more challenging than Question 1. Tabulating the information Next

5. When 6.0 g carbon burns completely to give carbon dioxide: a) how many grams of oxygen are consumed? b) what volume of CO 2 is formed when cooled to room temperature? (Assume 1 mole of any gas occupies 24 dm 3 at room temperature.) (This question has been taken and adapted from http://www.rsc.org/learn- chemistry/wiki/Quiz:GeneralA003:_Mole_calculations) Question 1. Tabulating the information Next

6. Q1. When 6.0 g carbon burns completely to give carbon dioxide: a) how many grams of oxygen are consumed? b) what volume of CO 2 is formed when cooled to room temperature? (Assume 1 mole of any gas occupies 24 dm 3 at room temperature.) In order to progress you will need the number (mole) ratio from the balanced equation, which is given below: C + O 2 → CO 2 Mole ratio C : O 2 : CO 2 1 :1 : 1 2 :1 : 1 1 :2 : 2 Select the correct mole ratio

7. Ratio feedback Question4. An impure sample of zinc powder with a mass of 5.84 g was reacted with hydrochloric acid until the reaction was complete. The hydrogen gas produced had a volume of 1.53 dm 3. Calculate the percentage purity of the zinc. (assume 1 mol of gas occupies 24 dm 3 under the conditions used for the reaction) Back In balanced equations the absence of a written number means the balancing number is 1. We omit the number 1 to avoid confusion. Please try again.

8. Q1. When 6.0 g carbon burns completely to give carbon dioxide: a) how many grams of oxygen are consumed? b) what volume of CO 2 is formed when cooled to room temperature? (Assume 1 mole of any gas occupies 24 dm 3 at room temperature.) QuantityCO2O2 CO 2 mass (g)N/A molar mass (g mol -1 ) 12.0N/A moles (mol) mole (number) ratio 111 volume (dm 3 )N/A Equation: C + O 2  CO 2 The first step is to enter the data we have from the question into the table. Select the box into which we can put data from the question.

9. Q1. When 6.0 g carbon burns completely to give carbon dioxide: a) how many grams of oxygen are consumed? b) what volume of CO 2 is formed when cooled to room temperature? (Assume 1 mole of any gas occupies 24 dm 3 at room temperature.) QuantityCO2O2 CO 2 mass (g)N/A molar mass (g mol -1 ) 12.0N/A moles (mol) mole (number) ratio 111 volume (dm 3 )N/A Equation: C + O 2  CO 2 The piece of data specific to this question is the mass of carbon. Back

10. Q1. When 6.0 g carbon burns completely to give carbon dioxide: a) how many grams of oxygen are consumed? b) what volume of CO 2 is formed when cooled to room temperature? (Assume 1 mole of any gas occupies 24 dm 3 at room temperature.) QuantityCO2O2 CO 2 mass (g)6.0N/A molar mass (g mol -1 ) 12.0N/A moles (mol) mole (number) ratio 111 volume (dm 3 )N/A We can also work out the molar mass that we will need. Select the correct molar mass of oxygen from the list below, then click Next. 16.0 32.0 12.0 44.0 RAM values C = 12.0, O = 16.0 Next

11. O 2 molar mass calc feedback Question4. An impure sample of zinc powder with a mass of 5.84 g was reacted with hydrochloric acid until the reaction was complete. The hydrogen gas produced had a volume of 1.53 dm 3. Calculate the percentage purity of the zinc. (assume 1 mol of gas occupies 24 dm 3 under the conditions used for the reaction) Back To calculate the molar mass of O 2 you need to add together the relative atomic masses of two oxygens.

12. Q1. When 6.0 g carbon burns completely to give carbon dioxide: a) how many grams of oxygen are consumed? b) what volume of CO 2 is formed when cooled to room temperature? (Assume 1 mole of any gas occupies 24 dm 3 at room temperature.) QuantityCO2O2 CO 2 mass (g)6.0N/A molar mass (g mol -1 ) 12.0N/A moles (mol) mole (number) ratio 111 volume (dm 3 )N/A We can also work out the molar mass that we will need. Select the correct molar mass of oxygen from the list below, then click Next. 16.0 32.0 12.0 44.0 RAM values C = 12.0, O = 16.0 Next

13. Q1. When 6.0 g carbon burns completely to give carbon dioxide: a) how many grams of oxygen are consumed? b) what volume of CO 2 is formed when cooled to room temperature? (Assume 1 mole of any gas occupies 24 dm 3 at room temperature.) QuantityCO2O2 CO 2 mass (g)6.0N/A molar mass (g mol -1 ) 12.032.0N/A moles (mol) mole (number) ratio 111 volume (dm 3 )N/A Select the substance from the reaction for which we have enough information to count the particles (calculate the moles), then click Next. RAM values C = 12.0, O = 16.0 Next

14. Moles calc feedback Question4. An impure sample of zinc powder with a mass of 5.84 g was reacted with hydrochloric acid until the reaction was complete. The hydrogen gas produced had a volume of 1.53 dm 3. Calculate the percentage purity of the zinc. (assume 1 mol of gas occupies 24 dm 3 under the conditions used for the reaction) Back You do not have enough information to calculate the moles of O 2 or CO 2 yet. You would need to know their masses (or their volumes as they are gases).

15. Q1. When 6.0 g carbon burns completely to give carbon dioxide: a) how many grams of oxygen are consumed? b) what volume of CO 2 is formed when cooled to room temperature? (Assume 1 mole of any gas occupies 24 dm 3 at room temperature.) QuantityCO2O2 CO 2 mass (g)6.0N/A molar mass (g mol -1 ) 12.032.0N/A moles (mol) mole (number) ratio 111 volume (dm 3 )N/A Select the correct calculation to count the particles (calculate the moles) of carbon, then click Next. RAM values C = 12.0, O = 16.0 Next 6.0 / 12.012.0 / 6.06.0 x 12.0

16. Carbon moles calc feedback Question4. An impure sample of zinc powder with a mass of 5.84 g was reacted with hydrochloric acid until the reaction was complete. The hydrogen gas produced had a volume of 1.53 dm 3. Calculate the percentage purity of the zinc. (assume 1 mol of gas occupies 24 dm 3 under the conditions used for the reaction) Back To calculate the moles of carbon use moles = mass / molar mass.

17. Q1. When 6.0 g carbon burns completely to give carbon dioxide: a) how many grams of oxygen are consumed? b) what volume of CO 2 is formed when cooled to room temperature? (Assume 1 mole of any gas occupies 24 dm 3 at room temperature.) QuantityCO2O2 CO 2 mass (g)6.0N/A molar mass (g mol -1 ) 12.032.0N/A moles (mol)0.5 mole (number) ratio 111 volume (dm 3 )N/A Select the correct calculation to count the particles (calculate the moles) of carbon, then click Next. RAM values C = 12.0, O = 16.0 Next 6.0 / 12.012.0 / 6.06.0 x 12.0

18. Q1. When 6.0 g carbon burns completely to give carbon dioxide: a) how many grams of oxygen are consumed? b) what volume of CO 2 is formed when cooled to room temperature? (Assume 1 mole of any gas occupies 24 dm 3 at room temperature.) QuantityCO2O2 CO 2 mass (g)6.0N/A molar mass (g mol -1 ) 12.032.0N/A moles (mol)0.5 mole (number) ratio 111 volume (dm 3 )N/A Now comes the step at the heart of every calculation of this kind: using the number of moles of one component in the equation and the mole ratio to work out the number of moles of the other components. Please click Next. Next Equation: C + O 2  CO 2

19. Q1. When 6.0 g carbon burns completely to give carbon dioxide: a) how many grams of oxygen are consumed? b) what volume of CO 2 is formed when cooled to room temperature? (Assume 1 mole of any gas occupies 24 dm 3 at room temperature.) QuantityCO2O2 CO 2 mass (g)6.0N/A molar mass (g mol -1 ) 12.032.0N/A moles (mol)0.5 mole (number) ratio 111 volume (dm 3 )N/A Select the number of moles of O 2 and CO 2 from the options below, then click Next. Next Equation: C + O 2  CO 2 1 and 10.5 and 0.5 16 and 221 and 0.5 0.5 and 1

20. O 2 and CO 2 moles calc feedback Question4. An impure sample of zinc powder with a mass of 5.84 g was reacted with hydrochloric acid until the reaction was complete. The hydrogen gas produced had a volume of 1.53 dm 3. Calculate the percentage purity of the zinc. (assume 1 mol of gas occupies 24 dm 3 under the conditions used for the reaction) Back To calculate the number of moles of O 2 and CO 2 use the mole ratio C : O 2 : CO 2 and the number of moles of C. The mole ratio is 1 : 1 : 1 from the balancing numbers in the equation. The number of moles of C is 0.5.

21. Q1. When 6.0 g carbon burns completely to give carbon dioxide: a) how many grams of oxygen are consumed? b) what volume of CO 2 is formed when cooled to room temperature? (Assume 1 mole of any gas occupies 24 dm 3 at room temperature.) QuantityCO2O2 CO 2 mass (g)6.0N/A molar mass (g mol -1 ) 12.032.0N/A moles (mol)0.5 mole (number) ratio 111 volume (dm 3 )N/A Select the number of moles of O 2 and CO 2 from the options below, then click Next. Next Equation: C + O 2  CO 2 1 and 10.5 and 0.5 16 and 221 and 0.5 0.5 and 1

22. Q1. When 6.0 g carbon burns completely to give carbon dioxide: a) how many grams of oxygen are consumed? b) what volume of CO 2 is formed when cooled to room temperature? (Assume 1 mole of any gas occupies 24 dm 3 at room temperature.) QuantityCO2O2 CO 2 mass (g)6.016N/A molar mass (g mol -1 ) 12.032.0N/A moles (mol)0.5 mole (number) ratio 111 volume (dm 3 )N/A Select the correct calculation to work out the mass of oxygen, then click Next. Next Equation: C + O 2  CO 2 6 x 0.5 12 x 0.5 32.0 x 0.5 44.0 x 0.5 32.0 / 0.5 0.5 / 32.0

23. oxygen mass calc feedback Question4. An impure sample of zinc powder with a mass of 5.84 g was reacted with hydrochloric acid until the reaction was complete. The hydrogen gas produced had a volume of 1.53 dm 3. Calculate the percentage purity of the zinc. (assume 1 mol of gas occupies 24 dm 3 under the conditions used for the reaction) Back To calculate the mass of oxygen use mass = moles x molar mass.

24. Q1. When 6.0 g carbon burns completely to give carbon dioxide: a) how many grams of oxygen are consumed? b) what volume of CO 2 is formed when cooled to room temperature? (Assume 1 mole of any gas occupies 24 dm 3 at room temperature.) QuantityCO2O2 CO 2 mass (g)6.016N/A molar mass (g mol -1 ) 12.032.0N/A moles (mol)0.5 mole (number) ratio 111 volume (dm 3 )N/A Select the correct calculation to work out the mass of oxygen, then click Next. Next Equation: C + O 2  CO 2 6 x 0.5 12 x 0.5 32.0 x 0.5 44.0 x 0.5 32.0 / 0.5 0.5 / 32.0

25. Q1. When 6.0 g carbon burns completely to give carbon dioxide: a) how many grams of oxygen are consumed? b) what volume of CO 2 is formed when cooled to room temperature? (Assume 1 mole of any gas occupies 24 dm 3 at room temperature.) QuantityCO2O2 CO 2 mass (g)6.016N/A molar mass (g mol -1 ) 12.032.0N/A moles (mol)0.5 mole (number) ratio 111 volume (dm 3 )N/A Select the correct calculation to work out the volume of CO 2, then click Next. Next Equation: C + O 2  CO 2 0.5 x 24 0.5 / 24 24 / 0.5 0.5 x 44

26. CO 2 volume calc feedback Question4. An impure sample of zinc powder with a mass of 5.84 g was reacted with hydrochloric acid until the reaction was complete. The hydrogen gas produced had a volume of 1.53 dm 3. Calculate the percentage purity of the zinc. (assume 1 mol of gas occupies 24 dm 3 under the conditions used for the reaction) Back To calculate the volume of a gas use volume = moles x 24 dm 3.

27. Q1. When 6.0 g carbon burns completely to give carbon dioxide: a) how many grams of oxygen are consumed? b) what volume of CO 2 is formed when cooled to room temperature? (Assume 1 mole of any gas occupies 24 dm 3 at room temperature.) QuantityCO2O2 CO 2 mass (g)6.016N/A molar mass (g mol -1 ) 12.032.0N/A moles (mol)0.5 mole (number) ratio 111 volume (dm 3 )N/A 12 Select the correct calculation to work out the volume of CO 2, then click Next. Next Equation: C + O 2  CO 2 0.5 / 24 24 / 0.5 0.5 x 44 0.5 x 24

28. Tabulating the information Next Well done. You have completed this question by tabulating the information. This technique is really useful to use on paper to get a good overview of what you know and don’t know and what you do have enough information to work out and what you don’t.

29. 10.0 cm 3 of a saturated solution of strontium hydroxide at 20°C was exactly neutralised by 13.15 cm 3 of 0.100 mol dm -3 hydrochloric acid. Calculate the solubility of strontium hydroxide in g dm -3. Question 2. Tabulating the information Next

30. Q2. 10.0 cm 3 of a saturated solution of strontium hydroxide at 20°C was exactly neutralised by 13.15 cm 3 of 0.100 mol dm -3 hydrochloric acid. Calculate the solubility of strontium hydroxide in g dm -3. Select the correct formula for strontium hydroxide: SrOH 2 Sr(OH) 2 Sr 2 OH 2 Sr(OH) 3

31. Formula feedback Question4. An impure sample of zinc powder with a mass of 5.84 g was reacted with hydrochloric acid until the reaction was complete. The hydrogen gas produced had a volume of 1.53 dm 3. Calculate the percentage purity of the zinc. (assume 1 mol of gas occupies 24 dm 3 under the conditions used for the reaction) Back Strontium is in group 2 so the strontium ion is Sr 2+. The hydroxide ion is OH -. Please try again.

32. Q2. 10.0 cm 3 of a saturated solution of strontium hydroxide at 20°C was exactly neutralised by 13.15 cm 3 of 0.100 mol dm -3 hydrochloric acid. Calculate the solubility of strontium hydroxide in g dm -3. Select the correct formula for strontium hydroxide: In order to progress you will need the number (mole) ratio from the balanced equation. The unbalanced equation is given below: Sr(OH) 2 + HCl → SrCl 2 + H 2 O Sr(OH) 2 : HCl Select the correct mole ratio 1 :1 2 :1 :2

33. Ratio feedback Question4. An impure sample of zinc powder with a mass of 5.84 g was reacted with hydrochloric acid until the reaction was complete. The hydrogen gas produced had a volume of 1.53 dm 3. Calculate the percentage purity of the zinc. (assume 1 mol of gas occupies 24 dm 3 under the conditions used for the reaction) Back 2HCl are needed for each Sr(OH) 2. Try again or practice balancing equations.practice

34. Q2. 10.0 cm 3 of a saturated solution of strontium hydroxide at 20°C was exactly neutralised by 13.15 cm 3 of 0.100 mol dm -3 hydrochloric acid. Calculate the solubility of strontium hydroxide in g dm -3. Select the correct formula for strontium hydroxide: QuantitySr(OH) 2 HCl volume (dm 3 )?? concentration (mol dm -3 ) ? moles (mol) mole (number) ratio12 MrMr N/A concentration (g dm -3 ) N/A Click on the correct group of data to put into the table from what we are given in the question. 10.0 13.15 0.100 0.0100 0.01315 0.100

35. Volume feedback Question4. An impure sample of zinc powder with a mass of 5.84 g was reacted with hydrochloric acid until the reaction was complete. The hydrogen gas produced had a volume of 1.53 dm 3. Calculate the percentage purity of the zinc. (assume 1 mol of gas occupies 24 dm 3 under the conditions used for the reaction) Back To convert the units of volume in cm 3 to dm 3 you need to divide by 1000.

36. Q2. 10.0 cm 3 of a saturated solution of strontium hydroxide at 20°C was exactly neutralised by 13.15 cm 3 of 0.100 mol dm -3 hydrochloric acid. Calculate the solubility of strontium hydroxide in g dm -3. Select the correct formula for strontium hydroxide: QuantitySr(OH) 2 HCl volume (dm 3 ) concentration (mol dm -3 ) moles (mol) mole (number) ratio12 MrMr N/A concentration (g dm -3 ) N/A Click on the moles which you have enough information to calculate. 10.0 13.15 0.100 0.0100 0.01315 0.100

37. Moles calc feedback Question4. An impure sample of zinc powder with a mass of 5.84 g was reacted with hydrochloric acid until the reaction was complete. The hydrogen gas produced had a volume of 1.53 dm 3. Calculate the percentage purity of the zinc. (assume 1 mol of gas occupies 24 dm 3 under the conditions used for the reaction) Back You do not have enough information to calculate the number of moles of Sr(OH) 2 yet. You know only its volume and would need to know its concentration as well to calculate it directly.

38. Q2. 10.0 cm 3 of a saturated solution of strontium hydroxide at 20°C was exactly neutralised by 13.15 cm 3 of 0.100 mol dm -3 hydrochloric acid. Calculate the solubility of strontium hydroxide in g dm -3. Select the correct formula for strontium hydroxide: QuantitySr(OH) 2 HCl volume (dm 3 )0.01000.01315 concentration (mol dm -3 ) 0.100 moles (mol) mole (number) ratio12 MrMr N/A concentration (g dm -3 ) N/A Click on the correct calculation to work out the number of moles of HCl, then click Next. 0.01315 / 0.1000.100 / 0.013150.01315 x 0.100 Next

39. HCl moles calc feedback Question4. An impure sample of zinc powder with a mass of 5.84 g was reacted with hydrochloric acid until the reaction was complete. The hydrogen gas produced had a volume of 1.53 dm 3. Calculate the percentage purity of the zinc. (assume 1 mol of gas occupies 24 dm 3 under the conditions used for the reaction) Back To calculate the number of moles of HCl use moles = concentration x volume (in dm 3 ).

40. Q2. 10.0 cm 3 of a saturated solution of strontium hydroxide at 20°C was exactly neutralised by 13.15 cm 3 of 0.100 mol dm -3 hydrochloric acid. Calculate the solubility of strontium hydroxide in g dm -3. Select the correct formula for strontium hydroxide: QuantitySr(OH) 2 HCl volume (dm 3 )0.01000.01315 concentration (mol dm -3 ) 0.100 moles (mol) mole (number) ratio12 MrMr N/A concentration (g dm -3 ) N/A Click on the correct calculation to work out the number of moles of HCl, then click Next. 0.01315 / 0.1000.100 / 0.013150.01315 x 0.100 0.001315 Next

41. Q2. 10.0 cm 3 of a saturated solution of strontium hydroxide at 20°C was exactly neutralised by 13.15 cm 3 of 0.100 mol dm -3 hydrochloric acid. Calculate the solubility of strontium hydroxide in g dm -3. Select the correct formula for strontium hydroxide: QuantitySr(OH) 2 HCl volume (dm 3 )0.01000.01315 concentration (mol dm -3 ) 0.100 moles (mol) mole (number) ratio12 MrMr N/A concentration (g dm -3 ) N/A Click on the correct calculation to work out the number of moles of Sr(OH) 2, then click Next. 0.001315 / 20.01315 / 20.01315 x 2 0.001315 0.01315 x 0.100 Next

42. Sr(OH) 2 moles calc feedback Question4. An impure sample of zinc powder with a mass of 5.84 g was reacted with hydrochloric acid until the reaction was complete. The hydrogen gas produced had a volume of 1.53 dm 3. Calculate the percentage purity of the zinc. (assume 1 mol of gas occupies 24 dm 3 under the conditions used for the reaction) Back To calculate the number of moles of Sr(OH) 2 use the mole ratio Sr(OH) 2 : HCl and the number of moles of HCl. The mole ratio is 1 : 2 from the balancing numbers in the equation so the number of moles of Sr(OH) 2 : HCl has to be 1 : 2.

43. Q2. 10.0 cm 3 of a saturated solution of strontium hydroxide at 20°C was exactly neutralised by 13.15 cm 3 of 0.100 mol dm -3 hydrochloric acid. Calculate the solubility of strontium hydroxide in g dm -3. Select the correct formula for strontium hydroxide: QuantitySr(OH) 2 HCl volume (dm 3 )0.01000.01315 concentration (mol dm -3 ) 0.100 moles (mol) mole (number) ratio12 MrMr N/A concentration (g dm -3 ) N/A 0.001315 / 20.01315 / 20.01315 x 2 0.001315 Next 0.01315 x 0.100 0.0006575 Click on the correct calculation to work out the number of moles of Sr(OH) 2, then click Next.

44. Q2. 10.0 cm 3 of a saturated solution of strontium hydroxide at 20°C was exactly neutralised by 13.15 cm 3 of 0.100 mol dm -3 hydrochloric acid. Calculate the solubility of strontium hydroxide in g dm -3. Select the correct formula for strontium hydroxide: QuantitySr(OH) 2 HCl volume (dm 3 )0.01000.01315 concentration (mol dm -3 ) 0.100 moles (mol)0.00065750.001315 mole (number) ratio12 MrMr N/A concentration (g dm -3 ) N/A 0.0006575 x 0.01000.0006575 / 0.0100 Next 0.0100 / 0.0006575 Click on the correct calculation to work out the concentration of Sr(OH) 2, then click Next.

45. Sr(OH) 2 concentration calc feedback Question4. An impure sample of zinc powder with a mass of 5.84 g was reacted with hydrochloric acid until the reaction was complete. The hydrogen gas produced had a volume of 1.53 dm 3. Calculate the percentage purity of the zinc. (assume 1 mol of gas occupies 24 dm 3 under the conditions used for the reaction) Back To calculate the concentration of Sr(OH) 2 use concentration = moles / volume (in dm 3 ).

46. Q2. 10.0 cm 3 of a saturated solution of strontium hydroxide at 20°C was exactly neutralised by 13.15 cm 3 of 0.100 mol dm -3 hydrochloric acid. Calculate the solubility of strontium hydroxide in g dm -3. Select the correct formula for strontium hydroxide: QuantitySr(OH) 2 HCl volume (dm 3 )0.01000.01315 concentration (mol dm -3 ) 0.100 moles (mol)0.00065750.001315 mole (number) ratio12 MrMr N/A concentration (g dm -3 ) N/A 0.0006575 x 0.01000.0006575 / 0.0100 Next 0.0100 / 0.0006575 Click on the correct calculation to work out the M r of Sr(OH) 2, then click Next. 0.06575

47. Q2. 10.0 cm 3 of a saturated solution of strontium hydroxide at 20°C was exactly neutralised by 13.15 cm 3 of 0.100 mol dm -3 hydrochloric acid. Calculate the solubility of strontium hydroxide in g dm -3. Select the correct formula for strontium hydroxide: QuantitySr(OH) 2 HCl volume (dm 3 )0.01000.01315 concentration (mol dm -3 ) 0.100 moles (mol)0.00065750.001315 mole (number) ratio12 MrMr N/A concentration (g dm -3 ) N/A 87.6 + 16.0 + 1.02 x 87.6 + 16.0 + 1.0 Next 87.6 + 2 x (16.0 + 1.0) Click on the correct calculation to work out the molar mass of Sr(OH) 2, then click Next. 0.06575 A r Values Sr = 87.6 O = 16.0 H = 1.0

48. Sr(OH) 2 molar mass calc feedback Question4. An impure sample of zinc powder with a mass of 5.84 g was reacted with hydrochloric acid until the reaction was complete. The hydrogen gas produced had a volume of 1.53 dm 3. Calculate the percentage purity of the zinc. (assume 1 mol of gas occupies 24 dm 3 under the conditions used for the reaction) Back To calculate the molar mass of Sr(OH) 2 you need to add the relative atomic masses of one strontium, two oxygens and two hydrogens.

49. Q2. 10.0 cm 3 of a saturated solution of strontium hydroxide at 20°C was exactly neutralised by 13.15 cm 3 of 0.100 mol dm -3 hydrochloric acid. Calculate the solubility of strontium hydroxide in g dm -3. Select the correct formula for strontium hydroxide: QuantitySr(OH) 2 HCl volume (dm 3 )0.01000.01315 concentration (mol dm -3 ) 0.100 moles (mol)0.00065750.001315 mole (number) ratio12 MrMr N/A concentration (g dm -3 ) N/A 87.6 + 16.0 + 1.02 x 87.6 + 16.0 + 1.0 Next 87.6 + 2 x (16.0 + 1.0) Click on the correct calculation to work out the concentration of Sr(OH) 2, then click Next. 0.06575 A r Values Sr = 87.6 O = 16.0 H = 1.0 121.6

50. Q2. 10.0 cm 3 of a saturated solution of strontium hydroxide at 20°C was exactly neutralised by 13.15 cm 3 of 0.100 mol dm -3 hydrochloric acid. Calculate the solubility of strontium hydroxide in g dm -3. Select the correct formula for strontium hydroxide: QuantitySr(OH) 2 HCl volume (dm 3 )0.01000.01315 concentration (mol dm -3 ) 0.100 moles (mol)0.00065750.001315 mole (number) ratio12 MrMr N/A concentration (g dm -3 ) N/A Next The next part needs a bit more thought – you know the concentration in mol dm -3 and have been asked to calculate it in g dm -3. Suppose you had 1 litre of this solution – you know how many moles of Sr(OH) 2 is dissolved in 1 litre – now you need to calculate what mass this would be in g. Press Next. 0.06575 121.6

51. Q2. 10.0 cm 3 of a saturated solution of strontium hydroxide at 20°C was exactly neutralised by 13.15 cm 3 of 0.100 mol dm -3 hydrochloric acid. Calculate the solubility of strontium hydroxide in g dm -3. Select the correct formula for strontium hydroxide: QuantitySr(OH) 2 HCl volume (dm 3 )0.01000.01315 concentration (mol dm -3 ) 0.100 moles (mol)0.00065750.001315 mole (number) ratio12 MrMr N/A concentration (g dm -3 ) N/A 0.06575 x 121.60.06575 / 121.6 Next 0.0006575 x 121.6 Click on the correct calculation to work out the concentration of Sr(OH) 2 in g dm -3, then click Next. 0.06575 121.6 Back

52. Sr(OH) 2 concentration calc feedback Question4. An impure sample of zinc powder with a mass of 5.84 g was reacted with hydrochloric acid until the reaction was complete. The hydrogen gas produced had a volume of 1.53 dm 3. Calculate the percentage purity of the zinc. (assume 1 mol of gas occupies 24 dm 3 under the conditions used for the reaction) Back To calculate the mass of Sr(OH) 2 in 1 litre use mass = moles (in 1 litre) x M r

53. Click on the correct calculation to work out the concentration of Sr(OH) 2 in g dm -3, then click Next. Q2. 10.0 cm 3 of a saturated solution of strontium hydroxide at 20°C was exactly neutralised by 13.15 cm 3 of 0.100 mol dm -3 hydrochloric acid. Calculate the solubility of strontium hydroxide in g dm -3. Select the correct formula for strontium hydroxide: QuantitySr(OH) 2 HCl volume (dm 3 )0.01000.01315 concentration (mol dm -3 ) 0.100 moles (mol)0.00065750.001315 mole (number) ratio12 MrMr N/A concentration (g dm -3 ) N/A 0.06575 x 121.60.06575 / 121.6 Next 0.0006575 x 121.6 0.06575 121.6 8.00 (3 sig. fig.)

54. Tabulating the information End Well done. You have completed the tabulating the information skill training. This is a useful skill to use when you have a calculation involving several bits of data. Good for titrations and almost essential for equilibrium constant calculations.