Zadanie 18
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…
Molar mass and mole calculations
Use molar mass in g mol⁻¹ to convert between mass in grams, amount in moles and number of particles with n = m / M, and chain these conversions in multi-step problems.
Tę umiejętność sprawdza 40 zadań wzorowanych na arkuszach IB z lat 2022–2026.
Zadania sprawdzające tę umiejętność: 40 Otwórz w wyszukiwarce z filtrami
Zadanie 1a
Determine the mass of sodium thiosulfate pentahydrate, Na2S2O3 ⋅ 5 H2O, needed to prepare 250.0 cm3 of a 0.2000 mol dm−3 solution.
- Materiał graficzny
Zadanie 4b
Calculate the percentage by mass of hydrogen in compound Y, giving your answer to four significant figures. Use section 7 of the data booklet.
Zadanie 5b
A second sample of Z was converted completely into vapour at a known temperature and pressure. (i) 0.148 g of the vapour occupied 63.7 cm3 at 110 °C and a pressure of 1.00 × 105 Pa. Calculate the amount, in mol, of Z in this sample. Use…
Zadanie 1a
Calculate the mass of solid potassium hydroxide that has to be weighed out.
Zadanie 4
4.06 g of hydrated magnesium chloride, MgCl2 ⋅ 6 H2O (Mr = 203), is dissolved in water to make 0.250 dm3 of solution. What is the concentration of chloride ions, in mol dm−3, in this solution? A. 0.0400 B. 0.0800 C.…
Zadanie 1c
A student compiles data on the solubility of bromine in water at different temperatures from several websites and textbooks. (i) Identify one problem that arises when the values from these sources are compared with one another. (ii) Each solubility is then…
- Tabela do uzupełnienia
Zadanie 3b
Suggest why the times measured for equal masses of the two metals are not a valid basis for comparing their reactivity.
Zadanie 4
A sealed flask contains 8.0 g of helium and 120 g of argon. What is the ratio of the number of atoms of argon to the number of atoms of helium in the flask? A. 0.067 B. 0.67 C. 1.5 D. 15
Zadanie 4b
The enthalpy of combustion of C19H40 is −12 660 kJ mol−1. (i) Calculate the maximum energy released when 1.50 g of C19H40 is burned completely. (ii) Determine the maximum temperature increase when 400.0 cm3 of water…
Zadanie 21
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…
Zadanie 1
Which compound has the highest percentage of carbon by mass? A. CH3CH2OH B. CH3CHO C. C3H8 D. C2H6
Zadanie 1c
At 150.0 °C and a pressure of 1.00 × 105 Pa, the vapour of A has a density of 2.45 × 103 g m−3. Determine the molar mass of A and hence its molecular formula. Use sections 1 and 2 of the data booklet.
Zadanie 2a
Demonstrate that these data are consistent with the formula MgSO4 ⋅ 7 H2O.
- Materiał graficzny
Zadanie 3a
An alloy contains three copper atoms for every zinc atom. Calculate the percentage by mass of copper in the alloy. Use section 7 of the data booklet.
Zadanie 6b
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…
Zadanie 10b
Ethane is used as a fuel. Calculate its specific energy, in kJ g−1, using the enthalpy of combustion in section 14 and the atomic masses in section 7 of the data booklet.
Zadanie 11b
Cyclopentane is a component of petrol. Its specific energy, the energy released per kilogram of fuel burned, is 4.69 × 107 J kg−1. Calculate the enthalpy of combustion of cyclopentane, C5H10, in kJ mol−1. Use…
Zadanie 1
A sample of ammonium sulfate, (NH4)2SO4, has a mass of 66.1 g. Mr = 132.17 How many moles of ammonium ions are present in the sample? A. 0.25 B. 0.50 C. 1.00 D. 1.50
Zadanie 4
A steel cylinder of volume 5.0 dm3 holds 2.0 g of helium at 27 °C. Ar(He) = 4.0; R = 8.31 J K−1 mol−1; PV = nRT Which expression gives the pressure of the helium, in Pa? A.…
Zadanie 1
Which quantity is measured in g mol−1? A. Relative molecular mass B. Amount of substance C. Avogadro constant D. Molar mass
Zadanie 2
What is the mass of one molecule of white phosphorus, P4? Use NA = 6.02 × 1023 mol−1. A. 5.1 × 10−23 g B. 2.1 × 10−22 g C. 4.9 × 1021 g D. 7.5 × 1025 g
Zadanie 4
A gas sample gave the experimental results below. Which expression gives the molar mass of the gas, in g mol−1? Ideal gas constant R = 8.31 J K−1 mol−1, PV = nRT A. B.…
- Tabela do uzupełnienia
Zadanie 5a
(i) Calculate the percentage of oxygen present in the double salt. (ii) Determine the empirical formula of the double salt. Use section 7 of the data booklet. (iii) The molar mass of the empirical formula is the same as the molar mass of the formula unit.…
Zadanie 5b
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…
Zadanie 6a
Glucose, C6H12O6, is oxidized in the body by respiration to carbon dioxide and water. The standard enthalpy of combustion of glucose is −2803 kJ mol−1. Determine the energy, in kJ, released by the complete oxidation of 12.5 g of glucose.
Zadanie 11b
The global warming potential (GWP) of a gas compares the heat it absorbs with the heat absorbed by an equal mass of carbon dioxide. The GWP of the refrigerant C2H2F4 is approximately 1300. Estimate the heat absorbed by one mole of C2H2F4 relative…
Zadanie 13b
One antacid tablet contains 1.50 g of calcium carbonate and a second tablet contains 1.50 g of magnesium hydroxide. Show by calculation that the tablet of magnesium hydroxide would neutralize more hydrochloric acid than the tablet of calcium carbonate.
Zadanie 1c
Calculate the percentage by mass of carbon in ethanoic acid.
Zadanie 1c
Calculate the mass percentage of oxygen in ethanoic acid.
Zadanie 2
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
Zadanie 2
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
Zadanie 3
A mixture of 44.1 g of propane and 192 g of oxygen is ignited and reacts until one reactant is used up, according to the equation. C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(l) Which substances are present in the vessel once the reaction has finished? A.…
Zadanie 3
A sealed vessel contains 4.41 g of propane and 24.0 g of oxygen, which react according to the equation. C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(l) Which substances are present in the vessel after the reaction is complete? A. CO2(g) and H2O(l)…
Zadanie 4c
Naturally occurring sulfur is a mixture of several isotopes. A sample was enriched in , giving the following composition: (i) Calculate the relative atomic mass of the enriched sample to two decimal places. (ii) The abundance of…
- Tabela do uzupełnienia
Zadanie 1b
In an experiment, calcium turnings were heated strongly in a crucible with a lid. The following data were recorded: (i) Calculate the amount of calcium, in mol, that was used. (ii) Determine the percentage uncertainty in the final mass of product. (iii) Assume…
- Tabela do uzupełnienia
Zadanie 2
Which sample contains the fewest moles of HBr? NA = 6.02 × 1023 mol−1. Molar volume of an ideal gas at STP = 22.7 dm3 mol−1. A. 0.647 g of HBr(g) B. 50.0 cm3 of…
Zadanie 1a
Calculate the percentage by mass of nitrogen in ammonium chloride. Use section 7 of the data booklet.
Zadanie 3
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
Zadanie 5a
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)