Chemistry SL Paper 1A, May 2025, TZ3

What is the number of hydrogen atoms in 0.0500 mol of hydrated magnesium sulfate, $\ce{MgSO4 * 7H2O}$? A. $3.01 \times 10^{22}$ B. $4.21 \times 10^{23}$ C. $2.11 \times 10^{23}$ D. $4.21 \times 10^{22}$

Which of the following could be the empirical formula of a compound with $M_\mathrm{r} = 70$? I. $\ce{CH2}$ II. $\ce{C4H6O}$ III. $\ce{C5H10}$ A. I and II only B. I and III only C. II and III only D. I, II and III

What volume of propane gas, in $\mathrm{cm^3}$, must be burned completely in oxygen to give 90 $\mathrm{cm^3}$ of carbon dioxide, all volumes being measured at the same temperature and pressure? $\ce{C3H8(g) + 5O2(g) -> 3CO2(g) + 4H2O(g)}$ A. 18 B. 30 C. 90 D.…

Which set correctly shows the numbers of protons, neutrons and electrons in $\ce{^{65}Cu^2+}$? A. Protons 29, neutrons 36, electrons 31 B. Protons 29, neutrons 36, electrons 27 C. Protons 27, neutrons 65, electrons 27 D. Protons 65, neutrons 65, electrons 29

How many electrons, at most, can be held in the fifth main energy level ($n = 5$) of an atom? A. 10 B. 25 C. 32 D. 50

Calcium ions and phosphate(V) ions combine to form an ionic compound. What is its formula? A. $\ce{CaPO4}$ B. $\ce{Ca2(PO4)3}$ C. $\ce{Ca3(PO4)2}$ D. $\ce{Ca3(PO3)2}$

A white crystalline solid has the properties shown in the table. Property Observation Melting point 770 °C Electrical conductivity of the solid none Electrical conductivity when molten good Solubility in water soluble Which structure is consistent with these…

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.…

Which list arranges the metals in order of increasing strength of metallic bonding (weakest first)? A. Rb, Mg, Na, Al B. Al, Mg, Na, Rb C. Rb, Na, Mg, Al D. Na, Rb, Al, Mg

Which monomer could produce this polymer? A. $\ce{CH2ClCH2Cl}$ B. $\ce{CHCl2CH3}$ C. $\ce{CH2=CHCl}$ D. $\ce{CH2=CCl2}$

Which element belongs to the f-block of the periodic table? A. Nd B. Fr C. Ta D. Pb

Which electron configuration is correct for a chromium atom, Cr, in its ground state? A. $\mathrm{[Ar]\,4s^1\,3d^5}$ B. $\mathrm{[Ar]\,4s^2\,3d^4}$ C. $\mathrm{[Ar]\,3d^6}$ D. $\mathrm{[Ar]\,4s^2\,4d^4}$

Which pair of elements reacts together most vigorously? A. Sodium and bromine B. Potassium and bromine C. Sodium and chlorine D. Potassium and chlorine

In which species does an atom have the oxidation state +5? I. $\ce{IF5}$ II. $\ce{H3PO4}$ III. $\ce{N2O4}$ A. I and II only B. I and III only C. II and III only D. I, II and III

Which two functional groups occur in both molecule P and molecule Q? A. Amino and a benzene ring B. Hydroxyl and ester C. Hydroxyl and a benzene ring D. Amino and hydroxyl

Which row correctly describes an endothermic reaction? A. The temperature of the surroundings rises and the products are more stable than the reactants. B. The temperature of the surroundings falls and the products are more stable than the reactants. C. The…

When 0.601 g of propan-1-ol is burned, the heat released raises the temperature of 250 $\mathrm{cm^3}$ of water by 8.00 K. What is the enthalpy of combustion of propan-1-ol, in $\mathrm{kJ\,mol^{-1}}$, calculated from these results? Specific heat capacity of…

Which route to chloroethane has an atom economy of 100 %? A. $\ce{C2H5OH + PCl5 -> C2H5Cl + POCl3 + HCl}$ B. $\ce{C2H6 + Cl2 -> C2H5Cl + HCl}$ C. $\ce{C2H5OH + HCl -> C2H5Cl + H2O}$ D. $\ce{C2H4 + HCl -> C2H5Cl}$

Which of the following could be used to follow the progress of the reaction between calcium carbonate and dilute nitric acid? $\ce{CaCO3(s) + 2HNO3(aq) -> Ca(NO3)2(aq) + H2O(l) + CO2(g)}$ I. A balance recording the mass of the open flask and its contents II. A…

Iron(III) ions and thiocyanate ions form a deep red complex ion in aqueous solution. $\ce{Fe^3+(aq) + SCN^-(aq) <=> [Fe(SCN)]^2+(aq)}$ Which of the following correctly predicts the effect of a change on this equilibrium? A. Adding iron(III) nitrate solution…

What amount of oxygen, in mol, is required to burn 8.72 g of butane, $\ce{C4H10(g)}$, completely? $M$(butane) = 58.14 $\mathrm{g\,mol^{-1}}$ A. 0.0231 B. 0.150 C. 0.975 D. 1.95

Which molecule has the shortest carbon to carbon bond? A. $\ce{C2H6}$ B. $\ce{C2H4}$ C. $\ce{C6H6}$ D. $\ce{C2H2}$

What are the electron domain geometries around the nitrogen atom and the carbon atom bonded directly to it, in alanine, $\ce{H2NCH(CH3)COOH}$? A. Trigonal planar (C), trigonal pyramidal (N) B. Tetrahedral (C), trigonal pyramidal (N) C. Trigonal pyramidal (C),…

What is the pH of a 0.020 $\mathrm{mol\,dm^{-3}}$ solution of nitric acid, $\ce{HNO3(aq)}$? A. 1.0 B. 1.7 C. 2.0 D. 12.3

Which of these solutions has a pH greater than 7 at 25 °C? A. $[\ce{H+}] = 1.0 \times 10^{-5}\ \mathrm{mol\,dm^{-3}}$ B. $[\ce{OH-}] = 1.0 \times 10^{-10}\ \mathrm{mol\,dm^{-3}}$ C. $[\ce{H3O+}] = 1.0 \times 10^{-11}\ \mathrm{mol\,dm^{-3}}$ D.…

Which equation correctly represents a reaction of dilute sulfuric acid? A. $\ce{H2SO4 + MgCO3 -> MgSO4 + CO2 + H2O}$ B. $\ce{H2SO4 + 2Ag -> Ag2SO4 + H2}$ C. $\ce{H2SO4 + 2KOH -> K2SO4 + H2}$ D. $\ce{H2SO4 + 2NaHCO3 -> Na2SO4 + 2H2O}$

Cadmium was added to separate solutions of silver nitrate and chromium(III) nitrate. $\ce{Cd(s) + 2AgNO3(aq) -> Cd(NO3)2(aq) + 2Ag(s)}$ $\ce{Cd(s) + Cr(NO3)3(aq)}$: no reaction Which list places the three metals in order from most reactive to least reactive?…

Molten lead(II) bromide, $\ce{PbBr2(l)}$, is electrolysed using inert electrodes. Which products form at the electrodes? A. Anode: $\ce{Br2}$, cathode: $\ce{Pb}$ B. Anode: $\ce{O2}$, cathode: $\ce{Pb}$ C. Anode: $\ce{Pb}$, cathode: $\ce{Br2}$ D. Anode:…

Reduction of which compound gives pentan-2-ol? A. Pentan-2-one B. Pentan-3-one C. Pentanal D. Pentanoic acid

Which is a conjugate acid-base pair? A. $\ce{H2CO3}$ / $\ce{CO3^2-}$ B. $\ce{H2SO4}$ / $\ce{SO4^2-}$ C. $\ce{HSO4-}$ / $\ce{SO4^2-}$ D. $\ce{CH3NH3+}$ / $\ce{CH3NH-}$