Use the mole ratio from a balanced equation to calculate the masses, gas volumes or solution concentrations of reactants and products, including titration calculations and back titrations.
Tę umiejętność sprawdza 51 zadań wzorowanych na arkuszach IB z lat 2022–2026.
(i) The first step is the catalytic oxidation of ammonia gas to nitrogen monoxide. 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g) Determine the volume, in dm3, of nitrogen monoxide produced from 20.0 g of ammonia, at STP, using section 2 of the data booklet.…
(i) Write a balanced equation for the reaction, including state symbols. (ii) Deduce what property of this reaction makes it possible to follow its rate by both methods. (iii) Magnesium carbonate was used in excess so that all of the acid would react.…
The student repeated the experiment using Method 2, with the same quantities of acid and solid. (i) Calculate the volume of gas that will have collected in the measuring cylinder once the reaction has finished, measured at T = 22 °C and…
(i) Determine the enthalpy of combustion of pentane, in kJ mol−1, using table 12 in the data booklet. C5H12(g) + 8 O2(g) → 5 CO2(g) + 6 H2O(g) (ii) Calculate the mass, in g, of carbon dioxide, CO2, produced when 45.0 g of pentane react with…
A sample of the sodium hydroxide solution is gradually added to 25.0 cm3 of an aqueous solution of an unknown organic acid, producing the following pH curve. Calculate the concentration of the unknown organic acid.
Excess magnesium is added to separate samples of aqueous acid. Which sample produces the greatest amount of hydrogen gas? Mr(HCl) = 36.46, Vm = 22.7 dm3 mol−1…
Sodium azide, NaN3 (Mr = 65.0), decomposes on heating to form sodium and nitrogen gas. 2 NaN3(s) → 2 Na(s) + 3 N2(g) What volume of nitrogen is produced from 26.0 g of sodium azide at STP? A. 6.05 dm3 B. 9.08 dm3…
(i) Suggest, giving a reason for each, two different safety precautions that should be taken when carrying out either of these preparations. (ii) Deduce the coefficients needed to balance the following equation for the reaction of silver with concentrated…
Gallium forms a sulfate of formula Ga2(SO4)3. (i) Both ionic and covalent bonding are present in this compound. State which particles are held together by each type of bond. (ii) Contrast covalent and ionic bonds in terms of what happens to the valence…
What volume of propane gas, in cm3, must be burned completely in oxygen to give 90 cm3 of carbon dioxide, all volumes being measured at the same temperature and pressure? C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g) A. 18 B. 30 C. 90 D.…
A chemist treated 22.99 g of galantamine with sulfuric acid to make the sulfate salt: 2 C17H21NO3 + H2SO4 → (C17H22NO3)2SO4 The mass of salt isolated was 24.65 g. Determine the percentage yield of the salt. Use section 7 of the data booklet.
What amount of oxygen, in mol, is required to burn 8.72 g of butane, C4H10(g), completely? M(butane) = 58.14 g mol−1 A. 0.0231 B. 0.150 C. 0.975 D. 1.95
(i) If the reaction has a percentage yield of 80 %, calculate the mass, in g, of benzene that would be produced from 2.0 kg of cyclohexane. (ii) Calculate the atom economy for this reaction, as a percentage.
Hexanoic acid, CH3(CH2)4COOH, is a weak acid. The graph shows how the pH changes during the titration of a 20.0 cm3 aqueous solution of hexanoic acid with aqueous sodium hydroxide. (i) Deduce an expression for the equilibrium constant, K,…
Sucrose, C12H22O11, is hydrolysed with excess water and the glucose formed is then fermented. C12H22O11(aq) + H2O(l) → 2 C6H12O6(aq) C6H12O6(aq) → 2 C2H5OH(aq) + 2 CO2(g) Mr of C12H22O11 = 342.34 Mr of…
Equal volumes of nitrogen and hydrogen are mixed and react according to the equation below. The volumes of the two reactants are measured at intervals. N2(g) + 3 H2(g) → 2 NH3(g) Which graph shows how the volumes of the two reactants change with time? A.…
What volume of hydrogen, in cm3, is produced at STP when 0.810 g of aluminium reacts with an excess of hydrochloric acid? 2 Al(s) + 6 HCl(aq) → 2 AlCl3(aq) + 3 H2(g) Molar volume of an ideal gas at STP = 22.7 dm3 mol−1 A. 341 B.…
A 20.00 cm3 sample of a solution containing 1.21 g of HA is titrated with 0.500 mol dm−3 sodium hydroxide solution, NaOH(aq). Exactly 27.40 cm3 of the NaOH(aq) is required to neutralize the acid completely. Determine…
When 10.0 cm3 of a gaseous hydrocarbon, CxHy, is burned completely, 70.0 cm3 of gaseous products is formed. This volume falls to 30.0 cm3 when the water vapour condenses. All volumes are measured at the same…
Propane hydrate, C3H8 ⋅ 17 H2O (Mr = 350), is a crystalline solid that can form in natural gas pipelines at low temperature. What mass of carbon dioxide is produced by the complete combustion of 17.5 g of propane hydrate? A. 2.20 g B. 6.60 g C. 17.5 g…
In a redox titration, dichromate(VI) ions are reduced to chromium(III) ions and iron(II) ions are oxidized to iron(III) ions. Cr2O72−(aq) reduced to Cr3+(aq) Fe2+(aq) oxidized to Fe3+(aq) What volume, in cm3, of…
(i) Determine the limiting reactant when 2.00 g of this powder reacts. (ii) Determine the volume, in dm3, of carbon dioxide released in the reaction in (i) at SATP. Use sections 1, 2 and 4 of the data booklet. (iii) A student collects 0.190…
8.00 mol of ammonia are mixed with 8.00 mol of oxygen. The equation for the reaction that occurs is shown below. 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g) What is the amount, in mol, of nitrogen(II) oxide, NO, produced, assuming that the reaction goes to…
Which species are present after 14 dm3 of ethyne has reacted with 20 dm3 of hydrogen to produce ethane? All gas volumes are measured at the same temperature and pressure. C2H2(g) + 2 H2(g) → C2H6(g) A. 14 dm3 of…
20.0 cm3 of propane is mixed with 150.0 cm3 of oxygen and burnt completely. C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(l) Determine the total volume of gas present once the products have cooled to the starting temperature and…
The iodine number of a fat or oil is the mass, in grams, of iodine that reacts with 100 g of the fat or oil. It is a measure of the degree of unsaturation. A 3.50 g sample of peanut oil reacts completely with 65.5 cm3 of…
A single dose of an antacid tablet contains 1.850 g of sodium hydrogencarbonate, NaHCO3, and 0.600 g of calcium carbonate, CaCO3. Stomach acid is hydrochloric acid. Mr(NaHCO3) = 84.01 and Mr(CaCO3) = 100.09 Determine the amount of…
Magnesium burns in oxygen. 2 Mg(s) + O2(g) → 2 MgO(s) What mass of magnesium oxide, in g, forms when 2.43 g of magnesium reacts with 3.41 dm3 of oxygen at STP? Mr(MgO) = 40.31; molar volume = 22.7 dm3 mol−1 A.…
In a titration, 25.00 cm3 of a 0.120 mol dm−3 solution of a weak monoprotic organic acid, HA, was neutralized by adding sodium hydroxide solution, NaOH(aq), from a burette. The pH curve obtained is shown. Determine the concentration,…
Petrol (gasoline) is a mixture of hydrocarbons and can be blended with bioethanol. The carbon footprint of a fuel can be expressed as the mass of carbon dioxide, in kg, produced per kg of fuel burned. Calculate the carbon footprint of heptane, C7H16, in…
Ethyl 4-hydroxybenzoate is a preservative used in some oral medicines. It was synthesized by heating 0.745 g of 4-hydroxybenzoic acid with excess ethanol and a few drops of concentrated sulfuric acid as catalyst. C7H6O3 + C2H6O ⇌ C9H10O3 + H2O Mr…
50 cm3 of gas X reacts with 20 cm3 of gas Y to form 20 cm3 of a gaseous product and leaves 10 cm3 of X unreacted. All volumes are measured at the same temperature and pressure. What is the empirical formula of…
The concentration of dissolved oxygen in a sample of pond water was determined by the Winkler method. The reactions that take place are:…
A 1.50 g sample of the double salt was dissolved in distilled water. Aqueous barium chloride was then added in excess, so that all the sulfate ions were precipitated as barium sulfate. (i) Formulate an ionic equation, including state symbols, for…
A volume of 21.6 cm3 of KOH(aq) neutralized 25.0 cm3 of the ethanoic acid solution. Determine the concentration of the ethanoic acid.
Methanol, CH3OH, can be used as a fuel. The standard enthalpy of combustion of methanol is −726 kJ mol−1. Calculate the mass of carbon dioxide produced per 1000 kJ of heat released by the complete combustion of methanol.
Hexane is a component of petrol. The equation for its combustion is: Determine the mass of carbon dioxide, in g, released for every 1 kJ of energy produced by the combustion of hexane. Use section 14 of the data…
Curve X (dashed) shows the volume of oxygen formed when 25 cm3 of 1.0 mol dm−3 hydrogen peroxide solution decomposes in the presence of a manganese(IV) oxide catalyst at 25 °C. 2 H2O2(aq) → O2(g) + 2 H2O(l) Which change would…
Magnesium hydroxide is the active ingredient of some indigestion remedies, which neutralize excess hydrochloric acid in the stomach. (i) Write an equation for the reaction of magnesium hydroxide with hydrochloric acid. (ii) Calculate the mass, in g, of…
Which hydrocarbon forms 4 mol of H2O for every 3 mol of CO2 upon complete combustion? A. C3H4 B. C3H6 C. C4H10 D. C3H8
A hydrocarbon burns completely in excess oxygen. The amounts of carbon dioxide and water formed are in the mole ratio 3 : 2. Which hydrocarbon is it? A. C2H6 B. C3H6 C. C3H4 D. C4H10
Metal M reacts with 8.00 g of oxygen to produce 28.0 g of the oxide MO2. What is the relative atomic mass of M? A. 20 B. 40 C. 80 D. 160
When 10.65 g of chlorine gas is passed over a metal M, 13.35 g of the compound MCl3 is formed and no reactant is left over. Which value is the relative atomic mass of M? A. 9 B. 18 C. 27 D. 133
A student heated 3.85 g of propanoic acid with an excess of the second reagent and isolated 3.12 g of the ester. Determine the percentage yield.
A fixed amount of magnesium reacts with hydrochloric acid, which is added in increasing amounts. After each addition the reaction is allowed to finish. Mg(s) + 2 HCl(aq) → MgCl2(aq) + H2(g) Which graph shows how the amount of hydrogen formed changes…
0.20 mol of ammonium hydrogencarbonate is heated gently until all of the solid has decomposed. NH4HCO3(s) → NH3(g) + H2O(g) + CO2(g) How many moles of gas are produced? A. 0.20 B. 0.40 C. 0.60 D. 0.80
A student heated 3.492 g of calcium turnings in a crucible with a lid and obtained 4.490 g of solid product. If the product is assumed to be calcium oxide only, the percentage yield is 92 %. (i) Evaluate whether the formation of calcium nitride, rather than…
A 0.460 g piece of sodium was placed in 250.0 cm3 of water. (i) Calculate the molar concentration of the sodium hydroxide solution formed. Assume that the volume of the solution is 250.0 cm3. (ii) Calculate the volume of hydrogen gas…
Solid ammonium chloride decomposes when heated to form two gases, ammonia and hydrogen chloride. (i) Write the chemical equation for this decomposition. (ii) Calculate the volume of ammonia produced at STP when an 8.00 g sample of ammonium chloride decomposes.…
How many moles of carbon dioxide are produced by the complete combustion of 14.5 g of butane, C4H10? Mr = 58 A. 0.25 B. 0.50 C. 1.00 D. 1.25
A sample of coal contains 1.20 % sulfur by mass. Calculate the amount, in mol, of sulfur dioxide produced when 400.0 g of this coal undergoes complete combustion. S(s) + O2(g) → SO2(g)
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