Part 7- Quantitative Chemistry Application Questions Triple Science How bonding and structure are related to the properties of substances A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes Chemical bonds, ionic, covalent and metallic Bonding Structure, and the Properties of Matter Use of amount of substance in relation to masses of pure substances Quantitative Chemistry Yield and atom economy of chemical reactions (Triple) Using concentrations of solutions in mol/dm3 (Triple) Chemical measurements, conservation of mass and the quantitative interpretation The periodic table Atomic Structure and the Periodic Table Paper 1 Chemical Changes Reactions of acids Reactivity of metals Reversible reactions and dynamic equilibrium The Rate and Extent of Chemical Change Chemistry Paper 2 Energy Changes Chemical cells and fuel cells (Triple) Exothermic and endothermic reactions Electrolysis Rate of reaction Reactions of alkenes and alcohols (Triple) Carbon compounds as fuels and feedstock Organic Chemistry Synthetic and naturally occurring polymers (Triple) Purity, formulations and chromatograph & 4.8.2 ID of gases Chemical Analysis Identification of ions by chemical and spectroscopic means (Triple) Chemistry of the Atmosphere Common atmospheric pollutants and their sources The composition and evolution of the Earth's atmosphere Carbon dioxide and methane as greenhouse gases Using Resources Life cycle assessment and recycling Using materials (Triple) Using the Earth's resources and obtaining potable water The Haber process and the use of NPK fertilisers (Triple)
4.3.1 Chemical measurements, conservation of mass and the quantitative interpretation AQA Chemistry (8462) from 2016 Topics C4.3 Quantitative chemistry Topic Student Checklist R A G State that mass is conserved and explain why, including describing balanced equations in terms of conservation of mass Explain the use of the multipliers in equations in normal script before a formula and in subscript within a formula Describe what the relative formula mass (Mr) of a compound is and calculate the relative formula mass of a compound, given its formula Calculate the relative formula masses of reactants and products to prove that mass is conserved in a balanced chemical equation Explain observed changes of mass during chemical reactions in non-enclosed systems using the particle model when given the balanced symbol equation Explain why whenever a measurement is made there is always some uncertainty about the result obtained 4.3.2 Use of amount of substance in relation to masses of pure substances 4.3.3 Yield and atom economy of chemical reactions 4.3.4 Using concentrations of solutions in mol/dm 3 HT ONLY: State that chemical amounts are measured in moles (mol) and explain what a mol is with reference to relative formula mass and Avogadro's constant HT ONLY: Use the relative formula mass of a substance to calculate the number of moles in a given mass of the substance HT ONLY: Calculate the masses of reactants and products when given a balanced symbol equation HT ONLY: Use moles to write a balanced equation when given the masses of reactants and products (inc changing the subject of the equation) HT ONLY: Explain the effect of limiting the quantity of a reactant on the amount of products in terms of moles or masses in grams Calculate the mass of solute in a given volume of solution of known concentration in terms of mass per given volume of solution HT ONLY: Explain how the mass of a solute and the volume of a solution is related to the concentration of the solution Chem ONLY: Explain why it is not always possible to obtain the calculated or expected amount of a product Chem ONLY: Calculate the theoretical amount of a product and percentage yield of a product using the formula % yield = mass of product made/max theoretical mass of product x 100 Chem & HT ONLY: Calculate the theoretical mass of a product from a given mass of reactant and the balanced equation for the reaction Chem ONLY: Describe atom economy as a measure of the amount of reactants that end up as useful products Chem ONLY: Calculate the percentage atom economy of a reaction to form a desired product using the equation % atom economy =RfM of desired product/sum of RfM of all reactants x 100 Chem & HT ONLY: Explain why a particular reaction pathway is chosen to produce a specified product, given appropriate data Chem & HT ONLY: Calculate the amount of solute (in moles or grams) in a solution from its concentration in mol/dm 3 Chem & HT ONLY: Calculate the concentration of a solution when it reacts completely with another solution of a known concentration Chem & HT ONLY: Describe how to carry out titrations of strong acids and strong alkalis and calculate quantities in titrations involving concentrations in mol/dm 3 and g/dm 3 Chem & HT ONLY: Explain how the concentration of a solution in mol/dm3 is related to the mass of the solute and the volume of the solution Chem & HT ONLY: Explain what the volume of one mole of any gas at room temperature is Chem & HT ONLY: Calculate the volume of a gas at room temperature and pressure from its mass and relative formula mass
A. Chemical measurements part 1 Chemical changes and conservation of mass 1. A piece of magnesium was heated in a crucible. a) Write a balance equation to show how the magnesium reacts with oxygen. (2). b) The mass of the crucible at the start of the reaction was 0.34g, but 0.56g at the end. Explain why the mass increased. (2). c) The student heated the crucible at the end of the reaction. What could the student do to make sure the reaction is complete? (2). d) Another student heated magnesium carbonate in a similar crucible, with the lid off. The reaction is shown below: MgCO3 (s) à MgO (s) + CO2 (g) Use the reaction to explain whether the mass would increase or decrease. Explain your answer. (3)
.. B. Chemical measurements part 2 Relative formula mass 1. Calculate the relative formula mass of Na 2CO 3. (1) 2. Calculate the relative atomic mass of Iron (with 5.8% 54 Fe, 91.8% 56 Fe, 2.1% 57 Fe and 0.3% 59 Fe). (2). C. Calculations part 1 Moles/Quantities/Balancing and Limiting factors (HT) 1. How many moles of sulfur atoms are there in: a) 9.8 grams of sulfur? (1) b) 16 tonnes of sulfur? (where 1 tonne = 1000kg) (1) 2. What is the mass of:
a) 0.04 moles of hydrogen H2? (1). b) 0.6 moles of sodium nitrate (NaNO3)? (2). 3. When calcium reacts with water it forms a solution of calcium hydroxide Ca(OH)2 and hydrogen gas. a) Write a balanced symbol equation, including the state symbols to show this equation. (3). b) Calculate how much calcium must be added to an excess of water to produce 3.7g of calcium hydroxide (2). 4. What mass of sodium chloride is produced when 5.3g of sodium carbonate reacts with excess dilute hydrochloric acid? (3) Na2CO3 + 2HCl à 2NaCl + H20 + CO2.
. 5. 0.010 moles of C4H10 reacts with oxygen as in the following equation: C 4H 10 + O 2 à CO 2 + H 20 1.76g of carbon dioxide and 0.90 of water are produced. Use this information to work out the balancing numbers for carbon dioxide and water. (4).. 6. 84 tonnes of nitrogen were mixed with 30 tonnes of hydrogen in the following equation: N2(g) + 3H2(g) 2NH3(g) a) Calculate the number of moles of nitrogen and hydrogen and calculate which reactant is the limiting factor. (3).. b) Calculate the maximum mass of ammonia that can be produced from 42 tonnes of nitrogen. (3).
D. Calculations part 2 Concentrations of solutions 1. A technician made up a solution of sodium hydroxide by placing 5.00g of solid sodium hydroxide in a flask and adding 100cm 3 of water. She placed in the stopper and shook until the reaction had stopped. What was the concentration of the solution in g/dm 3? (1) 2. A solution of copper chloride has a concentration of 300g/dm 3. What is the mass of copper chloride in 500cm 3 of the solution? (2). 3. Higher: Explain how the mass of a solute and the volume of water effect the concentration of a solution. (2). CHEMISTRY ONLY E. Quantities part 1 Percentage yield and atom economy 1. Give two possible reasons for the actual yield in a reaction being less that the maximum theoretical yield. (2).
2. Magnesium is burnt in air. The theoretical yield of magnesium oxide is 5g, but only 4.5g is produced. What is the percentage yield?. 3. Lead nitrate and potassium iodide solutions are mixed to make solid lead iodide. The solid is then separated using the following equipment: Suggest why the actual yield is less than the theoretical yield. (1) 4. Higher: 100g of magnesium carbonate is heated. It decomposes to make magnesium oxide and carbon dioxide. Calculate the theoretical yield of magnesium oxide made. (2) MgCO 3 à MgO + CO 2. 5. Calculate the atom economy for making hydrogen from the following reaction: (1) C(s) + 2H 2O(g) CO 2(g) + 2H 2(g)....
6. Suggest why industrial processes need as high an atom economy as possible? (2). F. Quantities part 2 Moles of solutions and gases (HT) 1. What is the concentration of a solution that has 0.25 mol of solute in 135cm 3 of solution? (1). 2. How many moles of copper sulfate are there in 40cm 3 of a 0.1 mol/dm 3 solution? (1). 3. Calculate the concentration in mol/dm 3 of a solution that has 2 mol of an alkali in 250 cm 3 of solution.(2).
4. What mass of sodium fluoride (NaF) is in 250cm 3 of a 2 mol/dm 3 solution? (2). 5. It takes 27.00cm 3 of hydrochloric acid to neutralise 25.00am 3 of sodium hydroxide at a concentration on 1.0 mol/dm 3. Calculate the concentration of hydrochloric acid in g/cm 3. (4).. 6. Calculate the volume of 0.7 mol of carbon dioxide gas at RTP. (1). 7. What is the volume 12.3g of butane gas (C4H10) at RTP? (3).