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 47 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…
(e) The propanoic acid obtained by the distillation was an aqueous solution with a volume of 22.5 cm3. Three 5.00 cm3 samples of this solution were titrated with 0.200 mol dm−3 NaOH to determine the accurate…
The ascorbic acid in the juice was determined by titration with a standard solution of iodine, I2. The method is based on the following redox reaction: C6H8O6(aq) + I2(aq) → C6H6O6(aq) + 2 I−(aq) + 2 H+(aq) (i) Deduce the oxidizing agent in this…
(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.
A sample of chalk is dissolved in acid and titrated with EDTA solution, represented as H2X2−. The titration requires 18.4 cm3 of 0.250 mol dm−3 EDTA. What is the mass of calcium carbonate, CaCO3, in the sample?…
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.
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 solution is prepared by dissolving 1.29 g of HA in water and making the volume up to 20.00 cm3. When the whole of this solution is titrated with 0.600 mol dm−3 sodium hydroxide, NaOH(aq), exactly 24.90 cm3 of the…
10.0 cm3 of a gaseous hydrocarbon, CxHy, is burned completely in exactly the required volume of oxygen. The gaseous products occupy 70.0 cm3. This falls to 30.0 cm3 once the water vapour present condenses, with…
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 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…
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…
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…
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…
Aluminium reacts with chlorine gas. 2 Al(s) + 3 Cl2(g) → 2 AlCl3(s) What mass of aluminium chloride, in g, forms when 2.70 g of aluminium reacts with 2.27 dm3 of chlorine at STP? Molar volume = 22.7 dm3 mol−1 A. 4.44 B. 8.89 C.…
In step 3, 3.00 × 10−4 mol of thiosulfate ions, S2O32−, reacted completely with the iodine formed in step 2. Determine the amount of O2, in mol, in the water sample.
Calculate the concentration of oxygen in the water sample, in g dm−3. If you could not answer (b), use 2.00 × 10−4 mol instead; this is not the correct value.
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. (i) Calculate the carbon footprint of heptane,…
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…
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…
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…
A 2.51 g sample of zinc carbonate is heated until it reaches constant mass. ZnCO3(s) → ZnO(s) + CO2(g) What is the mass of solid remaining? A. 0.88 g B. 1.63 g C. 2.51 g D. 3.39 g
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…
A 0.030 mol sample of magnesium is added to 20.0 cm3 of hydrochloric acid of concentration 1.0 mol dm−3. Mg(s) + 2 HCl(aq) → MgCl2(aq) + H2(g) How many moles of hydrogen gas are produced? A. 0.010 B. 0.020 C. 0.030 D. 0.060
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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