Rank the strengths of London dispersion forces, dipole-dipole forces and hydrogen bonds for similar molar masses, and use them to explain and compare the boiling points, volatility, solubility and electrical conductivity of covalent substances.
Tę umiejętność sprawdza 21 zadań wzorowanych na arkuszach IB z lat 2022–2026.
Pentan-2-ol can form by reacting pent-1-ene with water in the presence of an acid catalyst. CH2=CHCH2CH2CH3(g) + H2O(l) → CH3CH(OH)CH2CH2CH3(aq) ΔH⊖ = −84 kJ mol−1 (i) The first step of the mechanism for the formation of…
(i) State the names of the organic compounds used to produce the ester shown below. (ii) State the name of the by-product of this reaction. (iii) The compounds butan-1-ol and ethoxyethane have the same molar mass. Their structures are shown below. Explain,…
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…
At room temperature hydrogen cyanide is a liquid that evaporates readily, whereas ethyne, C2H2, which has almost the same molar mass, is a gas that boils at −84 °C. (i) Draw the Lewis formula of the hydrogen cyanide molecule, showing all valence…
Which row shows the gas and the conditions under which its behaviour is closest to that of an ideal gas? A. Hydrogen fluoride, HF, at high pressure and low temperature B. Methane, CH4, at high pressure and low temperature C. Hydrogen fluoride,…
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.…
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…
Methanol and butan-1-ol are members of the same homologous series. (i) Name the class of compound and the functional group that characterize this series. (ii) State the strongest intermolecular force between molecules of either alcohol. (iii) Predict one type…
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.
Pantothenic acid (vitamin B5) is added to some processed foods. Its structure is shown. Predict, giving one reason, whether pantothenic acid is soluble in vegetable oil.
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.
(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…
Spot X is known to be either glutamine or isoleucine. The structures of the two amino acids are shown. Predict, with reference to the structures, which amino acid is more likely to be in spot X. Use the RF values in the table.
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.…
Which substance is highly volatile in its pure state and gives a solution with high electrical conductivity in water? A. CH3Br B. KBr C. H2S D. HBr
Which substance has no intermolecular attraction other than London (dispersion) forces? A. ClF3 B. IF5 C. SeO2 D. SF6
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) 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…
Zapisujemy na Twoim urządzeniu to, bez czego serwis nie działa, np. zalogowanie. Plików analitycznych użyjemy tylko za Twoją zgodą. Szczegóły w polityce prywatności.