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What are the limiting reactant and the theoretical yield of hydrogen when 0.30 mol of aluminium reacts with 0.60 mol of hydrochloric acid? 2 Al(s) + 6 HCl(aq) → 2 AlCl3(aq) + 3 H2(g) In each option the limiting reactant is given first and the theoretical…
For which of these changes is ΔS negative? A. 2 SO2(g) + O2(g) → 2 SO3(g) B. NaNO3(s) → NaNO3(aq) C. Zn(s) + 2 HCl(aq) → ZnCl2(aq) + H2(g) D. CuCO3(s) → CuO(s) + CO2(g)
The table shows standard enthalpies of combustion. Which expression gives the enthalpy change, in kJ mol−1, of the following cracking reaction? C4H10(g) → C3H6(g) + CH4(g) A. −2878 + 2058 + 891 B. −2058 − 891 + 2878 C.…
Which are units for rate of reaction? A. s mol−1 dm3 B. mol dm−3 min C. mol dm−3 min−1 D. mol min−1
A reaction is spontaneous at low temperatures but becomes non-spontaneous when the temperature is raised. Which combination of signs of ΔH and ΔS is consistent with this behaviour? A. ΔH > 0 and ΔS > 0 B. ΔH < 0 and…
Which reaction has the largest positive entropy change? A. 2 SO2(g) + O2(g) → 2 SO3(g) B. NH4Cl(s) → NH3(g) + HCl(g) C. H2(g) + Cl2(g) → 2 HCl(g) D. NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)
Which changes increase the rate of the reaction? CaCO3(s) + 2 HCl(aq) → CaCl2(aq) + H2O(l) + CO2(g) I. Grinding the calcium carbonate into a fine powder II. Using a larger volume of hydrochloric acid of the same concentration III. Warming the…
Which route to chloroethane has an atom economy of 100 %? A. C2H5OH + PCl5 → C2H5Cl + POCl3 + HCl B. C2H6 + Cl2 → C2H5Cl + HCl C. C2H5OH + HCl → C2H5Cl + H2O D. C2H4 + HCl → C2H5Cl
One route to 2-bromopropane is the substitution of propane by bromine in ultraviolet light. C3H8(g) + Br2(g) → C3H7Br(g) + HBr(g) (C3H8 = 44.11 g mol−1, Br2 = 159.80 g mol−1, C3H7Br = 123.00…
Which species is an intermediate in the following reaction mechanism? NO2(g) + NO2(g) → NO3(g) + NO(g) NO3(g) + CO(g) → NO2(g) + CO2(g) A. NO2 B. NO3 C. NO D. CO2