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The diagram shows the energy profile of a reaction. P, Q and R are energies measured from the baseline of the potential energy axis. Which combination gives the activation energy of the forward reaction and the activation energy of the reverse reaction? A.…
The rate of the reaction between hydrogen and iodine vapour increases markedly when the temperature is raised from 500 K to 550 K. What is the main reason for this increase? A. The activation energy of the reaction is lowered. B. Molecules collide more…
What is the equilibrium constant expression for the following reaction? CH4(g) + H2O(g) ⇌ CO(g) + 3 H2(g) A. B. C.…
Which reactions involve the transfer of a proton? I. H2SO4(aq) + Zn(OH)2(s) → ZnSO4(aq) + 2 H2O(l) II. H2SO4(aq) + ZnCO3(s) → ZnSO4(aq) + H2O(l) + CO2(g) III. H2SO4(aq) + Zn(s) → ZnSO4(aq) + H2(g) A. I and II only B. I and III only C. II…
Calcium hydride is used as a portable source of hydrogen for fuel cells. It reacts with water as shown. CaH2(s) + 2 H2O(l) → Ca(OH)2(aq) + 2 H2(g) Which statement is correct? A. Calcium is reduced from +2 to 0. B. Hydrogen in CaH2 is oxidized from…
In a redox titration, dichromate(VI) ions are reduced to chromium(III) ions and iron(II) ions are oxidized to iron(III) ions. Cr2O72−(aq) reduced to Cr3+(aq) Fe2+(aq) oxidized to Fe3+(aq) What volume, in cm3, of…
What is the organic product of the reaction of 2-bromobutane with aqueous potassium hydroxide? A. but-1-ene B. butan-1-ol C. butan-2-ol D. 2-bromobutan-2-ol
Methane reacts with chlorine in the presence of ultraviolet light. Two observations about this reaction are listed. - Observation 1: in the initiation step, Cl−Cl bonds undergo homolytic fission but C−H bonds do not. - Observation 2: the…
Which species can act as an electrophile? A. CN− B. NH3 C. Br2 D. Br−
Which statements about pure carbon dioxide, CO2, are correct? I. It can be separated into carbon and oxygen by filtration. II. Its carbon and oxygen atoms are present in the same fixed ratio in every sample. III. Its atoms of the two elements are…