Zadanie 2a
Iodine crystals, I2(s), were sealed in a flask and left until an equilibrium was reached with violet vapour above the crystals. I2(s) ⇌ I2(g) (i) Name the change of state from I2(s) to I2(g) and state the type of force between…
Deduce which intermolecular forces (London dispersion, dipole-induced dipole, dipole-dipole, hydrogen bonding) act between given molecules from their size, polarity and the presence of hydrogen bonded to nitrogen, oxygen or fluorine.
Tę umiejętność sprawdza 30 zadań wzorowanych na arkuszach IB z lat 2022–2026.
Iodine crystals, I2(s), were sealed in a flask and left until an equilibrium was reached with violet vapour above the crystals. I2(s) ⇌ I2(g) (i) Name the change of state from I2(s) to I2(g) and state the type of force between…
The structure of lycopene is shown. To separate the lycopene, the filtered juice was shaken in a separating funnel with heptane, C7H16, and the mixture was left to form two immiscible layers, which were run into separate flasks. Predict which layer will…
The three isomers of C4H8O in the table have the same molar mass. What is the reason for the increase in boiling points? A. Increase in the number of covalent bonds per molecule B. Increase in molar mass C. Increase in the strength of intermolecular…
Kevlar owes its high strength to hydrogen bonds between neighbouring polymer chains. (i) Annotate the diagram below to show a hydrogen bond between the two chain sections, drawing the hydrogen bond as a dotted line. (ii) Outline how a hydrogen bond forms…
Discuss the melting points in the table below in terms of the bonding and/or intermolecular forces present in each substance.
Hydrogen fluoride boils at 20 °C, whereas hydrogen chloride boils at −85 °C. Which type of intermolecular force accounts for the much higher boiling point of hydrogen fluoride? A. Hydrogen bonding B. Dipole-dipole forces C. London (dispersion) forces D.…
4.81 g of sulfur was heated in a stream of chlorine gas until the reaction was complete. The mass of the chloride produced was 10.13 g. (i) Calculate how many atoms are present in this 4.81 g sample of sulfur. Use sections 2 and 7 of the data booklet. (ii)…
Outline why SO2 shows a greater deviation from the ideal gas model than carbon dioxide, CO2, does.
Deduce, giving a reason, which of the two dyes, orange or violet, is the more polar.
Which of these alkanes boils at the lowest temperature? A. CH3CH2CH2CH2CH3 B. C(CH3)4 C. (CH3)2CHCH2CH3 D. CH3CH2CH2CH2CH2CH3
The boiling points of the five simplest straight-chain primary amines, CH3NH2 to CH3(CH2)4NH2, and of the five simplest 1-fluoroalkanes, CH3F to CH3(CH2)4F, are plotted below against the number of carbon atoms in the molecule. An…
Butane, C4H10, and propenal have similar molar masses, yet propenal is the less volatile. Compare and contrast the intermolecular forces in the two substances to account for this difference.
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.
Paracetamol and phenacetin are two analgesics with similar structures. Predict, giving a reason, which of the two compounds is more soluble in water.
The graph shows the boiling points of the straight-chain alkenes with a terminal double bond, from ethene to hex-1-ene. (i) Explain why the boiling point rises from ethene to but-1-ene. (ii) A sample of but-1-ene is warmed from 250 K to 300 K at constant…
Young mussels were placed in a contaminated harbour. Samples were taken at regular intervals and the tin content of the soft tissue was determined. (i) The tin content follows a linear trend during the first six weeks. Deduce the equation for this part of the…
Nylon-6,6 is a polyamide used to make strong fibres. A section of one chain is shown; asterisks indicate continuation bonds. Compare and contrast the bonding and the intermolecular forces in nylon-6,6 and in graphite.
Which row correctly states the types of intermolecular force present between molecules of ethane, methylamine and fluoromethane? A. Ethane: London (dispersion) forces only; methylamine: London forces, dipole-dipole forces and hydrogen bonding; fluoromethane:…
(i) State the electron domain geometry of the water molecule. (ii) Deduce the Lewis (electron dot) structure of water and sketch its 3D molecular shape. (iii) Explain, with reference to the forces between molecules, why water has a higher boiling point than…
Which sequence shows the compounds in order of increasing boiling point? A. CH3CH2CH2OH < CH3COCH3 < CH3CH2CH2CH3 B. CH3COCH3 < CH3CH2CH2CH3 < CH3CH2CH2OH C. CH3CH2CH2CH3 < CH3CH2CH2OH < CH3COCH3 D.…
Ethanoic acid and propanone, CH3COCH3, each contain a C=O group, and their molar masses are close. (i) Considering the strongest intermolecular forces in each liquid, explain why propanone boils at a much lower temperature than ethanoic acid.…
Ethanoic acid and propanone, CH3COCH3, both contain a carbonyl group and have similar molar masses. (i) Explain, in terms of the strongest intermolecular forces present in each liquid, why propanone boils at a much lower temperature than ethanoic acid.…
Sheets of pyrolytic graphite, which consists of many stacked layers of carbon atoms, are used in some phones to spread heat away from the processor. A sheet conducts heat very well parallel to its surface but poorly through its thickness. Suggest an…
Palmitic acid, CH3(CH2)14COOH, and palmitoleic acid, CH3(CH2)5CH=CH(CH2)7COOH, which has a cis C=C double bond, both have a chain of sixteen carbon atoms. Predict which of the two fatty acids has the higher melting point and give two reasons for…
Which substance evaporates easily when pure and gives a strongly conducting solution in water? A. HBr B. KBr C. CH3Br D. NH3
Between the molecules of which substance do only London (dispersion) forces act? A. XeF4 B. SF4 C. ClF3 D. IF5
Acrylonitrile and but-1-ene have similar relative molecular masses but very different boiling points. Suggest why but-1-ene has a lower boiling point than acrylonitrile.
(i) Outline two differences between the bonding of carbon atoms in graphite and in diamond. (ii) Explain why fullerene, C60, sublimes at a much lower temperature than graphite.
What is the main attraction between molecules in liquid carbon tetrachloride, CCl4? A. Hydrogen bonding B. Ionic attraction C. Dipole–dipole forces D. London (dispersion) forces
(i) Deduce the structural formula and the empirical formula of B. (ii) Explain, with reference to Le Châtelier’s principle, the effect on the yield of B of using dilute rather than concentrated sulfuric acid as the catalyst. (iii) Compound A has a lower molar…
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