Topic 1 Review Ms. Kiely Coral Gables Senior High IB Chemistry SL
Bell-Ringer A 4 g sample of sodium hydroxide, NaOH, is dissolved in water and made up to 500 cm³ of aqueous solution. What is the concentration of the resulting solution? A. 0.1 mol dm ³ B. 0.2 mol dm ³ C. 0.5 mol dm ³ D. 1.0 mol dm ³ PERIOD 6: TOPIC 1, PART 9 SLIDES COMPLETE PV=nRT & VOLUME STOICHIOMETRY
Answer A 4 g sample of sodium hydroxide, NaOH, is dissolved in water and made up to 500 cm³ of aqueous solution. What is the concentration of the resulting solution? B. 0.2 mol dm ³ 4 g NaOH x 1 mol NaOH = 0.1 mol NaOH 40.00 g NaOH Concentration = number of moles of solute = 0.1 mol NaOH = 0.2 mol dm ³ volume of solution in dm³ 0.500 dm³
NEXT CLASS: TEST Exams in this class generally mimic the IB exam. 2nd and 6th period: Next class you will be given a test with both Papers 1 and 2. YOU MAY USE A CALCULATOR ON PAPER 2 ONLY.
Practice (i) Write an equation for the reaction between hydrochloric acid and calcium carbonate. (2) (ii) Determine the volume of 1.50 mol dm ³ hydrochloric acid that would react with exactly 1.25 g of calcium carbonate. (3) (iii) Calculate the volume of carbon dioxide, measured at 273 K and 1.01 10⁵ Pa, which would be produced when 1.25 g of calcium carbonate reacts completely with the hydrochloric acid. (2) (Total 9 marks)
Answer (i) 2HCl(aq) + CaCO3(s) CaCl2(aq) + CO2(g) + H2O(1); [1] for correct formulas, [1] for balanced, state symbols not essential. (ii) volume of HCl = 0.0167 dm³ OR 16.7 cm³ (iii) 1:1 ratio of CaCO₃ to CO₂ /use 0.0125 moles CO₂ (0.0125 22.4) = 0.28 dm³/280 cm³/2.8 10 ⁴m³
Practice A toxic gas, A, consists of 53.8% nitrogen and 46.2% carbon by mass. At 273 K and 1.01 10⁵ Pa, 1.048 g of A occupies 462 cm³. Determine the empirical formula of A. Calculate the molar mass of the compound and determine its molecular formula.
Answer Empirical formula = CN Molar mass = 50.9 g/mol Molecular formula = C₂N₂
Practice Assuming complete reaction, what volume of 0.200 mol dm ³ HCl(aq) is required to neutralize 25.0 cm³ of 0.200 mol dm ³ Ba(OH)₂(aq)? 2HCl + Ba(OH)₂ BaCl₂ + 2H₂O A. 12.5 cm³ B. 25.0 cm³ C. 50.0 cm³ D. 75.0 cm³
Answer Assuming complete reaction, what volume of 0.200 mol dm ³ HCl(aq) is required to neutralize 25.0 cm³ of 0.200 mol dm ³ Ba(OH)₂(aq)? 2HCl + Ba(OH)₂ BaCl₂ + 2H₂O A. 12.5 cm³ B. 25.0 cm³ C. 50.0 cm³ D. 75.0 cm³
Practice Ethyne, C₂H₂, reacts with oxygen according to the equation below. What volume of oxygen (in dm³) reacts with 0.40 dm³ of C₂H₂? 2C₂H₂(g) + 5O₂(g) 4CO₂(g) + 2H₂O(g) A. 0.40 B. 0.80 C. 1.0 D. 2.0
Answer Ethyne, C₂H₂, reacts with oxygen according to the equation below. What volume of oxygen (in dm³) reacts with 0.40 dm³ of C₂H₂? 2C₂H₂(g) + 5O₂(g) 4CO₂(g) + 2H₂O(g) A. 0.40 B. 0.80 C. 1.0 D. 2.0
Practice What volume of 0.500 mol dm ³ sulfuric acid solution is required to react completely with 10.0 g of calcium carbonate according to the equation below? CaCO₃(s) + H₂SO₄(aq) CaSO₄(aq) + H₂O(l) + CO₂(g) A. 100 cm3 B. 200 cm3 C. 300 cm3 D. 400 cm3
Answer What volume of 0.500 mol dm ³ sulfuric acid solution is required to react completely with 10.0 g of calcium carbonate according to the equation below? CaCO₃(s) + H₂SO₄(aq) CaSO₄(aq) + H₂O(l) + CO₂(g) A. 100 cm3 B. 200 cm3 C. 300 cm3 D. 400 cm3
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Practice Problems: 1. A solution of water and ammonia contains 2.10 x 10²³ molecules of H₂O and 8.00 x 10²¹ molecules of NH₃. How many moles of hydrogen atoms are present? 2. How many grams does 5.60 x 10²² molecules of SiO₂ weigh? 3. How many molecules are there in 21.6 grams of CH₄?
Answers: 1) 0.738 mol H atoms 2) 5.59 grams 3) 8.10 x 10²³ molecules
Practice Consider the following reaction. N₂(g) + 3H₂(g) 2NH₃(g) If the reaction is made to go to completion, what volume of ammonia, NH₃, (in dm³) can be prepared from 25 dm³ of nitrogen and 60 dm³ of hydrogen? All volumes are measured at the same temperature and pressure. A. 40 B. 50 C. 85 D. 120
Answer Consider the following reaction. N₂(g) + 3H₂(g) 2NH₃(g) If the reaction is made to go to completion, what volume of ammonia, NH₃, (in dm³) can be prepared from 25 dm³ of nitrogen and 60 dm³ of hydrogen? All volumes are measured at the same temperature and pressure. A. 40 B. 50 C. 85 D. 120
Practice Problems 1. What is the number of moles in 501 dm³ of He gas at STP? 2. What volume is occupied by 1.34 x 10²³ molecules of water vapor at STP? 3. How many atoms are in 32.5 dm³ of oxygen gas?
Answers: 1) 22.1 mol 2) 5.05 dm³ 3) 1.72 x 10²⁴ atoms
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