Zadanie 1a
The data for 0.6 g of catalyst seem anomalous. Suggest a possible cause.
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Chemistry HL Paper 3, May 2024, TZ1
Zadania wzorowane na pytaniach z tego arkusza: te same umiejętności, format i punktacja, inne dane i kontekst. Treści arkusza IB nie publikujemy.
Dodaj cały arkusz do zestawuZadanie 1b
The student hypothesized, from theory, that doubling the mass of CuO would double the rate of the catalysed reaction. (i) Suggest why it is important to state a hypothesis before an experiment is carried out. (ii) Explain how collision theory could…
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Zadanie 1c
The results in Figure 1 were processed to give Figure 2, which shows how the initial rate of reaction varies with the mass of catalyst. (i) Outline how the y-axis values in Figure 2 were obtained from the results in Figure 1. (ii) Suggest, giving a reason,…
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Zadanie 2a
Demonstrate that these data are consistent with the formula MgSO4 ⋅ 7 H2O.
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Zadanie 2b
The uncertainty in each mass reading is ±0.04 g. (i) Calculate the percentage uncertainty in the total mass loss. (ii) Using your answer to (i), calculate the absolute uncertainty in the number of moles of water per mole of MgSO4, that is the…
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Zadanie 2c
Deduce what the graph shows about the water in hydrated magnesium sulfate.
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Zadanie 3a
Potassium bromide, KBr, forms a three-dimensional lattice of ions. (i) Demonstrate how the electronegativity values and bonding triangle in sections 9 and 17 of the data booklet support an ionic model for this solid. (ii) Outline the nature of the…
Zadanie 3c
Sodium metal is manufactured by the electrolysis of molten sodium chloride. (i) Outline why sodium can be produced by electrolysis rather than by reduction with carbon. (ii) State the half-equation for the formation of sodium during the electrolysis.
Zadanie 4d
Poly(lactic-co-glycolic acid) is a condensation polymer used for dissolving surgical stitches. It is made from two monomers. A short section of the polymer chain is shown; the bonds ending in an asterisk continue the chain. Draw the functional groups needed to…
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Zadanie 5a
Glucose is made in the leaves of green plants by photosynthesis. Write the balanced equation for the overall reaction of photosynthesis.
Zadanie 5b
Glucose molecules are joined together in liver cells to form glycogen, a store of energy in animals. (i) Identify the type of reaction by which glucose forms glycogen, and the small molecule released in the reaction. (iii) State the type of reaction by which…
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 7a
The structural formula of a synthetic tripeptide P is shown. Circle every amide link in the structure.
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Zadanie 9a
A student used thin-layer chromatography to investigate the artificial colourings in a boiled sweet. A solution of the sweet was spotted on the start line and the plate was developed. The developed chromatogram is shown with a ruler in centimetres, whose zero…
- Tabela do uzupełnienia
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Zadanie 11
Citric acid gives lemon juice its sharp taste. It dissolves very readily in water. Its structure is shown. Explain why citric acid is soluble in water, with reference to its structure.
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Zadanie 13a
Write an equation for the complete combustion of ethane.
Zadanie 13b
Calculate the specific energy of ethane hydrate, in kJ g−1. Use section 14 of the data booklet.
Zadanie 14a
Natural gas, which is mainly methane, and coal, which is mainly carbon, are both burned in power stations. Outline why burning natural gas has a lower environmental impact than burning coal.
Zadanie 17b
Diclofenac, an anti-inflammatory drug, is often supplied as its sodium salt, which dissolves in water more readily than the diclofenac molecule itself. Circle the functional group that reacts with sodium hydroxide when this salt is prepared.
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Zadanie 18b
A student converts methyl 4-hydroxybenzoate (Mr = 152.15) into methyl 4-methoxybenzoate (Mr = 166.18) by replacing the hydrogen atom of the phenol group with a methyl group. The product was analysed in a mass spectrometer. Suggest how…
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Zadanie 20b
A buffer solution of pH 5.35 contains ethanoic acid and its conjugate base, the ethanoate ion. The pKa of ethanoic acid is 4.76. The concentration of ethanoic acid in the buffer is 1.50 × 10−2 mol dm−3. Calculate…
Zadanie 21b
Paracetamol and phenacetin are two analgesics with similar structures. Predict, giving a reason, which of the two compounds is more soluble in water.
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Zadanie 22a
Chloramphenicol is an antibiotic. A molecule of chloramphenicol contains two chiral carbon atoms. Identify the two chiral centres by marking each with an asterisk on the structure.
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Zadanie 24a
Compounds M and N both contain a 4-methoxyphenyl group, shown at the left of each structure. Their side chains are −CH2CH2COOH in M and −C(CH3)2OH in N. Predict the number of signals and the relative areas you would expect in the 1H NMR…
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Zadanie 24b
4-Phenylbutan-2-one is made by oxidizing 4-phenylbutan-2-ol. A sample of the product is contaminated with some unreacted alcohol. The infrared spectra of the pure ketone and of the pure alcohol are shown. Deduce, giving two reasons, which spectrum belongs to…
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