Zadanie 6
Chrome alum has the formula KCr(SO4)2 ⋅ 12 H2O. Which option shows the charges of the ions that make up this salt, in the order potassium, chromium, sulfate? A. K+, Cr2+, SO42− B. K+, Cr3+, SO43− C.…
Explain that ionic compounds form three-dimensional lattices described by empirical formulas, and account for their high melting points, low volatility, conductivity only when molten or dissolved, and solubility in polar solvents in terms of the lattice.
Tę umiejętność sprawdzają 23 zadania wzorowane na arkuszach IB z lat 2022–2026.
Chrome alum has the formula KCr(SO4)2 ⋅ 12 H2O. Which option shows the charges of the ions that make up this salt, in the order potassium, chromium, sulfate? A. K+, Cr2+, SO42− B. K+, Cr3+, SO43− C.…
Which properties are expected for the compound lithium bromide? A. Not soluble in water, low melting point, does not conduct electricity when solid, does not conduct electricity when molten B. Not soluble in water, low melting point, conducts electricity when…
Which of these changes has the largest negative standard enthalpy change, ΔH⊖? A. Na+(g) + Cl−(g) → NaCl(s) B. SrO(s) → Sr2+(g) + O2−(g) C. Ca2+(g) + 2 Cl−(g) → CaCl2(s) D. Mg2+(g) + O2−(g) → MgO(s)
Which ionic compound is expected to have the largest lattice enthalpy? A. MgO B. NaF C. KBr D. CaS
A white crystalline solid has the properties shown in the table. Which structure is consistent with these properties? A. Giant metallic lattice B. Giant covalent network C. Molecular covalent solid D. Giant ionic lattice
(i) Using sections 9 and 17 of the data booklet, and showing your working, deduce the type of bonding present in magnesium chloride, MgCl2, and its percentage covalent character. (ii) Assuming purely ionic bonding, and using sections 9 and 12 of the…
Part of the lattice of potassium bromide, KBr, is shown in an expanded view. Which statement about the lattice of potassium bromide is correct? A. Each bromide ion is in contact with six potassium ions. B. Neighbouring ions are held together by shared pairs of…
A solid has a very high melting point, does not conduct electricity when solid or when molten, and is insoluble in water and in non-polar solvents. Which type of structure does the solid have? A. Ionic lattice B. Metallic lattice C. Covalent molecular D.…
In which compound is the electrostatic attraction between the ions weakest? A. MgO B. CaO C. CaS D. MgS
An unknown element E has the six successive ionization energies given below. Which is the formula of the chloride of E? A. ECl B. ECl2 C. ECl3 D. ECl4
Ammonium ions and phosphate ions combine to form an ionic compound. What is its formula? A. NH4PO4 B. (NH4)2PO4 C. (NH4)3PO4 D. NH4(PO4)3
State, giving a reason, how the lattice enthalpy of lithium tartrate, Li2C4H4O6, would differ from that of sodium tartrate.
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…
Which type of substance has these properties? - very high melting point - does not conduct electricity as a solid or when molten - insoluble in water A. ionic B. metallic C. giant covalent D. simple molecular
Which compound has the largest lattice enthalpy? A. KI B. NaBr C. MgO D. CaS
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
In the solid state, calcium, Ca, and calcium chloride, CaCl2, are each built as a regular three-dimensional lattice. Predict the electrical conductivity of Ca(s) and of CaCl2(s), giving a reason for each.
Explain why the lattice enthalpy of potassium bromide, KBr, is lower than that of sodium bromide, NaBr.
Four solids, P, Q, R and S, were tested. The results are shown in the table. Which solid most likely has an ionic lattice structure? A. P B. Q C. R D. S
Calcium hydride, CaH2, is an ionic compound that forms a crystalline lattice of Ca2+ and H− ions. Deduce whether calcium hydride behaves as a Brønsted–Lowry acid or as a Brønsted–Lowry base, and justify your answer.
Which statement explains the high melting point of magnesium oxide? A. Strong covalent bonds between magnesium and oxygen atoms must be broken B. Strong intermolecular forces hold magnesium oxide molecules together C. A large amount of energy is needed to…
Which compound has the largest lattice enthalpy? A. MgBr2 B. NaCl C. CaCl2 D. MgCl2
A solution of barium hydroxide of concentration 0.10 mol dm−3 was added dropwise to 25 cm3 of copper(II) sulfate solution of concentration 0.10 mol dm−3 until 25 cm3 of the barium hydroxide solution had…
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