Zadanie 2c
Calculate the specific energy of ethanol for trial 5, in J g−1. Use sections 1 and 2 of the data booklet. mwater = 120.0 g
- Materiał graficzny
Calorimetry: Q = mcΔT and enthalpy change
Calculate the heat transferred with Q = mcΔT and the molar enthalpy change ΔH = -Q/n from calorimetry data for reactions in solution or combustion, extrapolate temperature-time graphs, and evaluate heat loss and other errors.
Tę umiejętność sprawdza 27 zadań wzorowanych na arkuszach IB z lat 2022–2026.
Zadania sprawdzające tę umiejętność: 27 Otwórz w wyszukiwarce z filtrami
Zadanie 2f
Suggest two ways in which the error in this experiment could be reduced.
- Materiał graficzny
Zadanie 4f
Ethanol can be used as a fuel. (i) Calculate the enthalpy change for the combustion of ethanol using section 12 of the data booklet. C2H5OH(g) + 3 O2(g) → 2 CO2(g) + 3 H2O(g) (ii) The enthalpy of formation of ethanol is defined from its elements. State,…
Zadanie 1b
In aqueous solution hydrogen cyanide behaves as a weak acid. (i) Write an equation for the ionization of hydrogen cyanide in water. (ii) Outline two ways in which a solution of 0.050 mol dm−3 HCN could be distinguished experimentally from…
- Materiał graficzny
Zadanie 9c
Calculate the rise in temperature of 400.0 cm3 of water heated by the complete combustion of 2.00 g of butan-1-ol, assuming that all the energy released is transferred to the water. Use sections 2 and 14 of the data booklet.
Zadanie 19
A liquid fuel was burned in a spirit burner and the heat released was used to warm water in a metal calorimeter, as shown. Q = mcΔT What is the standard enthalpy change of combustion, ΔHcombustion⊖, of the fuel according to the…
- Tabela do uzupełnienia
- Materiał graficzny
Zadanie 21
When 0.601 g of propan-1-ol is burned, the heat released raises the temperature of 250 cm3 of water by 8.00 K. What is the enthalpy of combustion of propan-1-ol, in kJ mol−1, calculated from these results? Specific heat capacity of…
Zadanie 23
A student stirred 0.030 mol of solid sodium hydrogencarbonate into 40 cm3 of a 1.0 mol dm−3 solution of ethanedioic acid. H2C2O4(aq) + 2 NaHCO3(s) → Na2C2O4(aq) + 2 CO2(g) + 2 H2O(l) The temperature of the solution fell from…
Zadanie 2a
Using sections 1 and 2 of the data booklet, determine the amount of heat that the water in beaker B gained from the metal.
Zadanie 2b
Assume that the heat released by the metal is equal to the heat absorbed by the water in beaker B, calculated in 2a. Determine the specific heat capacity of the metal. Use section 1 of the data booklet. If you have no answer to 2a, take the heat transferred to…
Zadanie 2c
Using the table below, state the name of the metal from which the block is made.
- Tabela do uzupełnienia
Zadanie 2d
Deduce, from the results obtained, two sources of systematic error in this procedure.
Zadanie 2a
(i) Suggest one hazard to health or safety in Student A's procedure. (ii) Student A plotted the highest temperature of each mixture against the volume of nitric acid. With a ruler, draw two straight lines of best fit: one following the rising set of points and…
- Materiał graficzny
Zadanie 2b
Student B pipetted 30.00 cm3 of the potassium hydroxide solution into a 150 cm3 glass beaker and added the nitric acid from a burette in portions of 4.00 cm3, recording the steady temperature after each addition. (i) From a…
- Tabela do uzupełnienia
Zadanie 5b
The enthalpy of combustion of C15H32 is −10 040 kJ mol−1. (i) Calculate the maximum amount of energy that the complete combustion of 1.75 g of pentadecane can release. (ii) The energy from burning the 1.75 g sample is used to heat…
Zadanie 2a
(i) Calculate, in J, the thermal energy gained by the water. Use sections 1 and 2 of the data booklet. (ii) Determine the percentage uncertainty of the energy value from (i). (iii) Suggest one way to reduce the effect of random uncertainty on the final result.
- Materiał graficzny
Zadanie 2b
(i) Determine the molar enthalpy of combustion of butan-1-ol, in kJ mol−1, and state one assumption you made. If you did not obtain an answer to 2a(i), use 20 000 J, but this is not the correct value. (ii) Calculate the percentage error of your…
- Materiał graficzny
Zadanie 2c
A second spirit burner contains hexane, C6H14, instead of butan-1-ol. Determine whether hexane would release more or less energy per gram than butan-1-ol. Use section 14 of the data booklet.
- Materiał graficzny
Zadanie 14
A 52.0 g piece of zinc at 90.0 °C is dropped into 80.0 cm3 of water at 20.0 °C. The final temperature of the water is 24.0 °C. The specific heat capacity of zinc is…
Zadanie 16
A student determined the enthalpy change of combustion of ethanol by burning it in a spirit burner under a copper can containing 150 cm3 of water. The value obtained was less exothermic than the literature value. Which modification would improve the…
- Materiał graficzny
Zadanie 18
50.0 cm3 of copper(II) sulfate solution of concentration 0.200 mol dm−3 is placed in an insulated cup. Excess zinc powder is added and the mixture is stirred. The maximum temperature increase is 10.4 °C.…
Zadanie 4c
A 15.40 g block of pure copper is heated from 20.0 °C to 45.0 °C. Calculate the heat energy absorbed, in J. The specific heat capacity of copper is 0.385 J g−1 K−1.
Zadanie 6b
The enthalpy change of combustion of ethanol was investigated in a school laboratory. A spirit burner containing ethanol was used to heat water in a metal can. A total of 0.0250 mol of ethanol was burned. The following data were recorded. (i) Calculate the…
- Tabela do uzupełnienia
- Materiał graficzny
Zadanie 15
When 50 cm3 of 1.0 mol dm−3 HNO3 is mixed with 50 cm3 of 1.0 mol dm−3 KOH in a calorimeter, the temperature of the solution rises by 6.0 °C. What is the temperature rise, in °C, when 50…
Zadanie 13
Identical pieces of zinc, each of mass 0.65 g, are added to two solutions of hydrochloric acid, X and Y, at the same initial temperature. Each reaction takes place in an identical insulated container and the mixture is stirred. Which statement is…
- Tabela do uzupełnienia
- Materiał graficzny
Zadanie 14
Burning 0.500 g of propan-1-ol, CH3CH2CH2OH, heats 200 g of water by 12.4 K. Specific heat capacity of water: 4.18 J g−1 K−1. What is the enthalpy of combustion of propan-1-ol, in…
Zadanie 1d
A student investigates the dissolution of ammonium chloride in water as the basis of an instant cold pack, in which solid ammonium chloride is kept apart from water by a thin membrane. The enthalpy change when one mole of solid ammonium chloride dissolves in…